chore(deps): bump protobuf in /functions/v2/datastore/hello-datastore (#13437)

Bumps [protobuf](https://github.com/protocolbuffers/protobuf) from 4.25.6 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@v4.25.6...v4.25.8)

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

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

Author: dependabot[bot]

functions/v2/datastore/hello-datastore/requirements.txt

@@ -2,5 +2,5 @@ functions-framework==3.8.2
 google-events==0.14.0
 google-cloud-datastore==2.20.2
 google-api-core==2.17.1
-protobuf==4.25.6
+protobuf==4.25.8
 cloudevents==1.11.0