GitLab

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.19.1 to 1.21.1.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](https://github.com/grpc/grpc-go/compare/v1.19.1...v1.21.1)
Signed-off-by: dependabot-preview[bot] <support@dependabot.com>