track tool dependencies in the repo

[csuzhangxc]

Feature Request

Describe the feature you'd like:

We use some tools to generate/check the code, including the protobuf generator, grpc-gateway pkgs, etc.

We need to track these dependencies in the repo, then all of the contributors can use the same version of them.

Teachability, Documentation, Adoption, Migration Strategy:

• https://github.com/twitchtv/retool
• https://github.com/golang/go/wiki/Modules#how-can-i-track-tool-dependencies-for-a-module