chore: update release-please configs to include cloudbuild yaml files (…

…#2326)

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Fixes #<issue_number_goes_here> ☕️

.github/release-please.yml

@@ -3,4 +3,4 @@ bumpMinorPreMajor: true
 handleGHRelease: true
 primaryBranch: main
 manifest: true
-extraFiles: ["WORKSPACE"]
+extraFiles: ["WORKSPACE", ".cloudbuild/cloudbuild.yaml", ".cloudbuild/cloudbuild-test-a.yaml", ".cloudbuild/cloudbuild-test-b.yaml" ]