This is something I've pondered myself, but haven't got a chance to play around with. My idea was simply to integrate it with make (or whatever build tool/script you prefer) where it pulls the .proto file from master in git unless you specify a branch. The downside is that you aren't versioning the protoc file with the client.

It's probably best to separate the proto file for server and client and treat it as a dependency.

If you're using a mono-repo the solution is possibly a little simpler.