pkg/plugin/grpcecosystem/grpcgateway/protoc-gen-grpc-gateway.go#L28-L29
return &protoc.PluginConfiguration{
Label: label.New("build_stack_rules_proto", "plugin/grpc-ecosystem/grpc-gateway", "protoc-gen-grpc-gateway"),
there is no grpc-ecosystem subdir under plugin/ in this repo
using it without a label causes this error
$ bazel run //proto/path/to/my/generated/build/file:types_go_compiled_sources.update
ERROR: no such package '@@build_stack_rules_proto+//plugin/grpc-ecosystem/grpc-gateway': BUILD file not found in directory 'plugin/grpc-ecosystem/grpc-gateway' of external repository @@build_stack_rules_proto+. Add a BUILD file to a directory to mark it as a package.