fix: bump release-please from 15.13.0 to 16.3.1

Bumps [release-please](https://github.com/googleapis/release-please) from 15.13.0 to 16.3.1.
- [Release notes](https://github.com/googleapis/release-please/releases)
- [Changelog](https://github.com/googleapis/release-please/blob/main/CHANGELOG.md)
- [Commits](googleapis/release-please@v15.13.0...v16.3.1)

---
updated-dependencies:
- dependency-name: release-please
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>