SG: add protoc dependencies to sg setup

Created by: camdencheek

This adds protoc, protoc-gen-go, and protoc-gen-go-grpc to the list of sg setup dependencies. They are not used yet, but will be required once we have generated gRPC files.

Dependencies are as documented here. I've tested that these are the minimum set of dependencies needed to generate gRPC services from .proto files.

Test plan

Manually tested that the checks and auto-fix work on my MacOS machine.