go get -u github.com/pseudomuto/protoc-gen-doc/cmd/protoc-gen-doc
package google.golang.org/genproto/googleapis/api/annotations: google.golang.org/genproto is a custom import path for https://github.com/googleapis/go-genproto, but /Users/XXX/go/src/google.golang.org/genproto is checked out from https://github.com/google/go-genproto
go get -u github.com/pseudomuto/protoc-gen-doc/cmd/protoc-gen-doc