chore: add release-please config for protobuf-4.x (#2620)

* chore: add release-please config for protobuf-4.x * chore: generate libraries at Wed Dec 3 19:03:35 UTC 2025 * Change release type from java-backport to java-yoshi * Refactor release-please.yml to remove redundancy Removed duplicate bumpMinorPreMajor setting for java-yoshi. --------- Co-authored-by: cloud-java-bot <cloud-java-bot@google.com>

Author: diegomarquezp

.github/release-please.yml

@@ -50,3 +50,7 @@ branches:
  handleGHRelease: true
  releaseType: java-backport
  branch: 1.140.x
+ - handleGHRelease: true
+ releaseType: java-yoshi
+ branch: protobuf-4.x-rc
+ manifest: true