Using buildGoModule did not work for this package, and produced the
error "main module (google.golang.org/grpc) does not contain package
google.golang.org/grpc/cmd/protoc-gen-go-grpc". Since buildGoModule and
buildGoPackage both seem in common use and both have their advantages
(https://github.com/NixOS/nixpkgs/issues/84826) just using
buildGoPackage seems like a neat solution here.
