Bump com.google.api:api-common in /plugins/repository-gcs

Bumps com.google.api:api-common from 1.8.1 to 2.20.0.

---
updated-dependencies:
- dependency-name: com.google.api:api-common
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

plugins/repository-gcs/build.gradle

@@ -52,7 +52,7 @@ versions << [
 ]
 
 dependencies {
-  api 'com.google.api:api-common:1.8.1'
+  api 'com.google.api:api-common:2.20.0'
   api 'com.google.api:gax:2.32.0'
   api 'com.google.api:gax-httpjson:0.103.1'