chore(deps): update dependency com.google.protobuf:protobuf-java to v3.21.8 (#1827)

Author: renovate-bot

dependencies.properties

@@ -23,7 +23,7 @@ version.gax_httpjson=0.104.3-SNAPSHOT
 # Versions for dependencies which actual artifacts differ between Bazel and Gradle.
 # Gradle build depends on prebuilt maven artifacts, while Bazel build depends on Bazel workspaces
 # with the sources.
-version.com_google_protobuf=3.21.7
+version.com_google_protobuf=3.21.8
 version.google_java_format=1.15.0
 version.io_grpc=1.50.1