Unfortunately, there is no common practice, although the main goal that you should achieve is to store proto files in one version control repository.
During my investigation, I’ve found some interesting blog posts about that subject:
- https://www.bugsnag.com/blog/libraries-for-grpc-services
- https://www.crowdstrike.com/blog/improving-performance-and-reliability-of-microservices-communication-with-grpc/
- https://medium.com/namely-labs/how-we-build-grpc-services-at-namely-52a3ae9e7c35
They covers much of gRPC workflow considerations. Hope that helps!