Deprecated usage of github.com/golang/protobuf/ptypes

[codefromthecrypt]

The most recent release of golang/protobuf formally deprecated github.com/golang/protobuf/ptypes

golang/protobuf#1306

// Deprecated: Use the "google.golang.org/protobuf" module instead.
module github.com/golang/protobuf

I noticed the code generator still uses the old namespace. Can there be a flag or other approach to use a non-deprecated one?

[akonradi]

Is this as simple as replacing one with the other in PGV? If so, feel free to send a PR! Unless there's a compelling reason, we should just migrate instead of trying to maintain compatibility with both.