gapic-generator-java feat(gax): add protobuf version tracking to headers

Update the Java client libraries to report the runtime version of Protobuf as part of the existing x-goog-api-client request header.

Tested: java-cloud-library api (billing) and hand written api (storage)

Sep 13 '24 15:09 ldetmer

LGTM w/ addition of Showcase tests showing gRPC + httpjson clients are both providing the new headers.

Looking for approval from @blakeli0

Sep 16 '24 20:09 burkedavison

Thank you for the showcase tests - LGTM.

Sep 18 '24 21:09 burkedavison

Adding Do Not Merge for now since we plan to release this together with the protobuf runtime upgrade.

Sep 19 '24 16:09 blakeli0

Adding Do Not Merge for now since we plan to release this together with the protobuf runtime upgrade.

Understood about DNM, but is this verbally LGTM?

Sep 20 '24 17:09 ldetmer

Quality Gate passed for 'gapic-generator-java-root'

Oct 15 '24 21:10 sonarqubecloud[bot]

Oct 15 '24 21:10 sonarqubecloud[bot]