Bump google.golang.org/grpc from 1.53.0 to 1.56.3

Bumps [google.golang.org/grpc](https://github.com/grpc/grpc-go) from 1.53.0 to 1.56.3.
- [Release notes](https://github.com/grpc/grpc-go/releases)
- [Commits](grpc/grpc-go@v1.53.0...v1.56.3)

---
updated-dependencies:
- dependency-name: google.golang.org/grpc
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

go.mod

@@ -3,9 +3,9 @@ module github.com/containerd/protobuild
 go 1.13
 
 require (
-	github.com/golang/protobuf v1.5.2
+	github.com/golang/protobuf v1.5.3
 	github.com/pelletier/go-toml v1.8.1
-	golang.org/x/tools v0.3.0
-	google.golang.org/grpc v1.53.0
-	google.golang.org/protobuf v1.28.1
+	golang.org/x/tools v0.7.0
+	google.golang.org/grpc v1.56.3
+	google.golang.org/protobuf v1.30.0
 )