Bumps [Google.Protobuf](https://github.com/protocolbuffers/protobuf) from 3.15.7 to 3.15.8. - [Release notes](https://github.com/protocolbuffers/protobuf/releases) - [Changelog](https://github.com/protocolbuffers/protobuf/blob/master/generate_changelog.py) - [Commits](https://github.com/protocolbuffers/protobuf/compare/v3.15.7...v3.15.8) Signed-off-by: dependabot-preview[bot] <support@dependabot.com>pull/3160/head