feat: Regenerate libraries with protobuf-4.x#11816

diegomarquezp wants to merge 4 commits intoprotobuf-4.x-rcgoogleapis/google-cloud-java:protobuf-4.x-rcfrom

feature/protobuf-4.x-generationgoogleapis/google-cloud-java:feature/protobuf-4.x-generationCopy head branch name to clipboard