chore(deps): bump protobuf (#13436)

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 4.25.3 to 4.25.8.
- [Release notes](https://github.com/protocolbuffers/protobuf/releases)
- [Changelog](https://github.com/protocolbuffers/protobuf/blob/main/protobuf_release.bzl)
- [Commits](protocolbuffers/protobuf@v4.25.3...v4.25.8)

---
updated-dependencies:
- dependency-name: protobuf
  dependency-version: 4.25.8
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

dataflow/flex-templates/pipeline_with_dependencies/requirements.txt

@@ -218,7 +218,7 @@ proto-plus==1.23.0
     #   google-cloud-spanner
     #   google-cloud-videointelligence
     #   google-cloud-vision
-protobuf==4.25.3
+protobuf==4.25.8
     # via
     #   apache-beam
     #   google-api-core