diff --git a/.github/.OwlBot.lock.yaml b/.github/.OwlBot.lock.yaml
index b631901..757c9dc 100644
--- a/.github/.OwlBot.lock.yaml
+++ b/.github/.OwlBot.lock.yaml
@@ -13,5 +13,5 @@
 # limitations under the License.
 docker:
   image: gcr.io/cloud-devrel-public-resources/owlbot-python:latest
-  digest: sha256:f792ee1320e03eda2d13a5281a2989f7ed8a9e50b73ef6da97fac7e1e850b149
-# created: 2022-05-05T15:17:27.599381182Z
+  digest: sha256:81ed5ecdfc7cac5b699ba4537376f3563f6f04122c4ec9e735d3b3dc1d43dd32
+# created: 2022-05-05T22:08:23.383410683Z
diff --git a/.github/auto-approve.yml b/.github/auto-approve.yml
new file mode 100644
index 0000000..311ebbb
--- /dev/null
+++ b/.github/auto-approve.yml
@@ -0,0 +1,3 @@
+# https://github.com/googleapis/repo-automation-bots/tree/main/packages/auto-approve
+processes:
+  - "OwlBotTemplateChanges"
diff --git a/CHANGELOG.md b/CHANGELOG.md
index fbf6fa9..cd28d3c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,17 @@
 # Changelog
 
+## [2.8.1](https://github.com/googleapis/python-containeranalysis/compare/v2.8.0...v2.8.1) (2022-06-03)
+
+
+### Bug Fixes
+
+* **deps:** require protobuf <4.0.0dev ([#290](https://github.com/googleapis/python-containeranalysis/issues/290)) ([26720af](https://github.com/googleapis/python-containeranalysis/commit/26720af5f15534c7459bb6bcf3711334b79e3aeb))
+
+
+### Documentation
+
+* fix changelog header to consistent size ([#291](https://github.com/googleapis/python-containeranalysis/issues/291)) ([3bd6974](https://github.com/googleapis/python-containeranalysis/commit/3bd6974f040bcac04fe2ec3061f7ff284ab98aed))
+
 ## [2.8.0](https://github.com/googleapis/python-containeranalysis/compare/v2.7.3...v2.8.0) (2022-05-05)
 
 
@@ -12,14 +24,14 @@
 
 * **deps:** require grpc-google-iam-v1 >=0.12.4 ([dfb21df](https://github.com/googleapis/python-containeranalysis/commit/dfb21df83a30d33f31dc67b8a50cc5d5cf9e9ccf))
 
-### [2.7.3](https://github.com/googleapis/python-containeranalysis/compare/v2.7.2...v2.7.3) (2022-03-07)
+## [2.7.3](https://github.com/googleapis/python-containeranalysis/compare/v2.7.2...v2.7.3) (2022-03-07)
 
 
 ### Bug Fixes
 
 * allow credentials to propagate when using get_grafeas_client() ([#251](https://github.com/googleapis/python-containeranalysis/issues/251)) ([237c204](https://github.com/googleapis/python-containeranalysis/commit/237c2043fd526457fc04ebc5d53346067c011c28))
 
-### [2.7.2](https://github.com/googleapis/python-containeranalysis/compare/v2.7.1...v2.7.2) (2022-03-04)
+## [2.7.2](https://github.com/googleapis/python-containeranalysis/compare/v2.7.1...v2.7.2) (2022-03-04)
 
 
 ### Bug Fixes
@@ -27,7 +39,7 @@
 * **deps:** require google-api-core>=1.31.5, >=2.3.2 ([#250](https://github.com/googleapis/python-containeranalysis/issues/250)) ([b35be6a](https://github.com/googleapis/python-containeranalysis/commit/b35be6a5d9fe629f4a575c66fa6e198e784f3035))
 * **deps:** require proto-plus>=1.15.0 ([b35be6a](https://github.com/googleapis/python-containeranalysis/commit/b35be6a5d9fe629f4a575c66fa6e198e784f3035))
 
-### [2.7.1](https://github.com/googleapis/python-containeranalysis/compare/v2.7.0...v2.7.1) (2022-02-11)
+## [2.7.1](https://github.com/googleapis/python-containeranalysis/compare/v2.7.0...v2.7.1) (2022-02-11)
 
 
 ### Bug Fixes
@@ -41,7 +53,7 @@
 
 * add api key support ([#236](https://github.com/googleapis/python-containeranalysis/issues/236)) ([a6ea0c6](https://github.com/googleapis/python-containeranalysis/commit/a6ea0c69d61c1f07220c42d32bf05a93b35db664))
 
-### [2.6.3](https://github.com/googleapis/python-containeranalysis/compare/v2.6.2...v2.6.3) (2022-01-13)
+## [2.6.3](https://github.com/googleapis/python-containeranalysis/compare/v2.6.2...v2.6.3) (2022-01-13)
 
 
 ### Bug Fixes
@@ -49,7 +61,7 @@
 * **deps:** require grafeas 1.4.1 ([16d27f7](https://github.com/googleapis/python-containeranalysis/commit/16d27f73742d969a62394cf1de4cce85849ea92a))
 * include the compliance protos ([#222](https://github.com/googleapis/python-containeranalysis/issues/222)) ([16d27f7](https://github.com/googleapis/python-containeranalysis/commit/16d27f73742d969a62394cf1de4cce85849ea92a))
 
-### [2.6.2](https://www.github.com/googleapis/python-containeranalysis/compare/v2.6.1...v2.6.2) (2021-11-01)
+## [2.6.2](https://www.github.com/googleapis/python-containeranalysis/compare/v2.6.1...v2.6.2) (2021-11-01)
 
 
 ### Bug Fixes
@@ -62,7 +74,7 @@
 
 * list oneofs in docstring ([5de0b09](https://www.github.com/googleapis/python-containeranalysis/commit/5de0b093d7495f9d46c332463aa68a7a5995e317))
 
-### [2.6.1](https://www.github.com/googleapis/python-containeranalysis/compare/v2.6.0...v2.6.1) (2021-10-28)
+## [2.6.1](https://www.github.com/googleapis/python-containeranalysis/compare/v2.6.0...v2.6.1) (2021-10-28)
 
 
 ### Bug Fixes
@@ -83,14 +95,14 @@
 
 * add context manager support in client ([#192](https://www.github.com/googleapis/python-containeranalysis/issues/192)) ([5274a93](https://www.github.com/googleapis/python-containeranalysis/commit/5274a933bd7abec9528168fa0530388536269c4c))
 
-### [2.4.2](https://www.github.com/googleapis/python-containeranalysis/compare/v2.4.1...v2.4.2) (2021-09-24)
+## [2.4.2](https://www.github.com/googleapis/python-containeranalysis/compare/v2.4.1...v2.4.2) (2021-09-24)
 
 
 ### Bug Fixes
 
 * add 'dict' annotation type to 'request' ([42c8c64](https://www.github.com/googleapis/python-containeranalysis/commit/42c8c646630810189a971796c921b30a2d2b419f))
 
-### [2.4.1](https://www.github.com/googleapis/python-containeranalysis/compare/v2.4.0...v2.4.1) (2021-07-26)
+## [2.4.1](https://www.github.com/googleapis/python-containeranalysis/compare/v2.4.0...v2.4.1) (2021-07-26)
 
 
 ### Bug Fixes
@@ -138,21 +150,21 @@
 * add async client to %name_%version/init.py ([b427e90](https://www.github.com/googleapis/python-containeranalysis/commit/b427e9091d4afc482c8d9fd6ff4510ad3b740820))
 * **deps:** add packaging requirement ([#135](https://www.github.com/googleapis/python-containeranalysis/issues/135)) ([3f0bd3a](https://www.github.com/googleapis/python-containeranalysis/commit/3f0bd3af9d809150a81933601bee5b9de0ff834a))
 
-### [2.2.3](https://www.github.com/googleapis/python-containeranalysis/compare/v2.2.2...v2.2.3) (2021-04-02)
+## [2.2.3](https://www.github.com/googleapis/python-containeranalysis/compare/v2.2.2...v2.2.3) (2021-04-02)
 
 
 ### Bug Fixes
 
 * require google-api-core >= 1.22.2 ([#103](https://www.github.com/googleapis/python-containeranalysis/issues/103)) ([74be886](https://www.github.com/googleapis/python-containeranalysis/commit/74be8869363254d3551a58634c299abcfb18e682))
 
-### [2.2.2](https://www.github.com/googleapis/python-containeranalysis/compare/v2.2.1...v2.2.2) (2021-03-25)
+## [2.2.2](https://www.github.com/googleapis/python-containeranalysis/compare/v2.2.1...v2.2.2) (2021-03-25)
 
 
 ### Bug Fixes
 
 * effective severity attribute error ([#104](https://www.github.com/googleapis/python-containeranalysis/issues/104)) ([913251a](https://www.github.com/googleapis/python-containeranalysis/commit/913251aa5535612460cd7ed6139c3cb5b7c7cc3f))
 
-### [2.2.1](https://www.github.com/googleapis/python-containeranalysis/compare/v2.2.0...v2.2.1) (2021-02-09)
+## [2.2.1](https://www.github.com/googleapis/python-containeranalysis/compare/v2.2.0...v2.2.1) (2021-02-09)
 
 
 ### Documentation
@@ -189,7 +201,7 @@
 
 * move to microgen. See the [Migration Guide](https://github.com/googleapis/python-containeranalysis/blob/release-v2.0.0/UPGRADING.md) for details. ([#33](https://www.github.com/googleapis/python-containeranalysis/issues/33)) ([6098905](https://www.github.com/googleapis/python-containeranalysis/commit/60989058883a0ae35f3b913d6a06741c73186203))
 
-### [1.0.3](https://www.github.com/googleapis/python-containeranalysis/compare/v1.0.2...v1.0.3) (2020-08-11)
+## [1.0.3](https://www.github.com/googleapis/python-containeranalysis/compare/v1.0.2...v1.0.3) (2020-08-11)
 
 
 ### Bug Fixes
@@ -197,7 +209,7 @@
 * Use different versions of pytest for python 2 and python3 [([#2558](https://www.github.com/googleapis/python-containeranalysis/issues/2558))](https://github.com/GoogleCloudPlatform/python-docs-samples/issues/2558) ([7d21641](https://www.github.com/googleapis/python-containeranalysis/commit/7d21641eb50f574784ae7dfbb1d25a0d0af14699))
 * **deps:** add upper bound for grafeas ([#30](https://www.github.com/googleapis/python-containeranalysis/issues/30)) ([5ca8f79](https://www.github.com/googleapis/python-containeranalysis/commit/5ca8f7981349ed86438185f02681225f059cc9d9))
 
-### [1.0.2](https://www.github.com/googleapis/python-containeranalysis/compare/v1.0.1...v1.0.2) (2020-07-16)
+## [1.0.2](https://www.github.com/googleapis/python-containeranalysis/compare/v1.0.1...v1.0.2) (2020-07-16)
 
 
 ### Bug Fixes
@@ -209,7 +221,7 @@
 
 * add multiprocessing note ([#21](https://www.github.com/googleapis/python-containeranalysis/issues/21)) ([be29088](https://www.github.com/googleapis/python-containeranalysis/commit/be290885cef76ffdd27afb44cd858c6a89d4f280))
 
-### [1.0.1](https://www.github.com/googleapis/python-containeranalysis/compare/v1.0.0...v1.0.1) (2020-06-16)
+## [1.0.1](https://www.github.com/googleapis/python-containeranalysis/compare/v1.0.0...v1.0.1) (2020-06-16)
 
 
 ### Bug Fixes
diff --git a/samples/snippets/requirements.txt b/samples/snippets/requirements.txt
index 8ed3df3..df9fc6a 100644
--- a/samples/snippets/requirements.txt
+++ b/samples/snippets/requirements.txt
@@ -1,6 +1,6 @@
-google-cloud-pubsub==2.12.0
-google-cloud-containeranalysis==2.7.3
-grafeas==1.4.3
+google-cloud-pubsub==2.12.1
+google-cloud-containeranalysis==2.8.0
+grafeas==1.4.4
 pytest==7.1.2
 flaky==3.7.0
 mock==4.0.3
diff --git a/setup.py b/setup.py
index 950d210..528fbc6 100644
--- a/setup.py
+++ b/setup.py
@@ -22,7 +22,7 @@
 
 name = "google-cloud-containeranalysis"
 description = "Container Analysis API API client library"
-version = "2.8.0"
+version = "2.8.1"
 release_status = "Development Status :: 5 - Production/Stable"
 dependencies = [
     # NOTE: Maintainers, please do not require google-api-core>=2.x.x
@@ -30,7 +30,8 @@
     # https://github.com/googleapis/google-cloud-python/issues/10566
     "google-api-core[grpc] >= 1.31.5, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0",
     "grpc-google-iam-v1 >= 0.12.4, <1.0.0dev",
-    "proto-plus >= 1.15.0",
+    "proto-plus >= 1.15.0, <2.0.0dev",
+    "protobuf >= 3.19.0, <4.0.0dev",
     "grafeas >=1.4.1, <2.0dev",
 ]
 extras = {"libcst": "libcst >= 0.2.5"}
diff --git a/testing/constraints-3.6.txt b/testing/constraints-3.6.txt
index a9d02d6..324b99d 100644
--- a/testing/constraints-3.6.txt
+++ b/testing/constraints-3.6.txt
@@ -10,3 +10,4 @@ grpc-google-iam-v1==0.12.4
 proto-plus==1.15.0
 libcst==0.2.5
 grafeas==1.4.1
+protobuf==3.19.0
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
index e69de29..324b99d 100644
--- a/testing/constraints-3.7.txt
+++ b/testing/constraints-3.7.txt
@@ -0,0 +1,13 @@
+# This constraints file is used to check that lower bounds
+# are correct in setup.py
+# List *all* library dependencies and extras in this file.
+# Pin the version to the lower bound.
+#
+# e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
+# Then this file should have foo==1.14.0
+google-api-core==1.31.5
+grpc-google-iam-v1==0.12.4
+proto-plus==1.15.0
+libcst==0.2.5
+grafeas==1.4.1
+protobuf==3.19.0
diff --git a/tests/unit/gapic/containeranalysis_v1/test_container_analysis.py b/tests/unit/gapic/containeranalysis_v1/test_container_analysis.py
index cdb3994..550369f 100644
--- a/tests/unit/gapic/containeranalysis_v1/test_container_analysis.py
+++ b/tests/unit/gapic/containeranalysis_v1/test_container_analysis.py
@@ -14,7 +14,13 @@
 # limitations under the License.
 #
 import os
-import mock
+
+# try/except added for compatibility with python < 3.8
+try:
+    from unittest import mock
+    from unittest.mock import AsyncMock
+except ImportError:
+    import mock
 
 import grpc
 from grpc.experimental import aio