This already exists as part of the grpc package.

I submitted the review request for python-grpcio on September 28 2018.

The grpc package was submitted for review on November 2018, its packager
aparently unaware of mine.

The latter got reviewed and approved quickly though, so when I tried to
build this for the first time the python3-grpcio package already existed
and Koji refused my build.

Since the other package was in first, and since it builds the whole gRPC
suite, not just the Python bindings, I'm retiring this one.