Bumps [github.com/golang/protobuf](https://github.com/golang/protobuf) from 1.4.3 to 1.5.1. - [Release notes](https://github.com/golang/protobuf/releases) - [Commits](https://github.com/golang/protobuf/compare/v1.4.3...v1.5.1) Signed-off-by: dependabot-preview[bot] <support@dependabot.com>