Hi, I'm working on building a gRPC service with Scala, but it seems like the grpc field for the Scala protobuf_sources target isn't being used, and the gRPC service code isn't being generated whether I set the field to true or not. I'm pretty sure I've identified what needs to change for the grpc field to be used, so I'd like to open an issue and submit a PR unless I'm missing something obvious.