publics/golang__protobuf @ 89193ac6024453e4e0884eebdceabbe6efdfa656

Joe Tsai 09b5b46567 cmd/protoc-gen-go: revert Enum simplication		6 lat temu
..
pb2	09b5b46567 cmd/protoc-gen-go: revert Enum simplication	6 lat temu
pb3	872b50047a cmd/protoc-gen-go: generate oneof types seperately	6 lat temu