As part of the consolidation of core libraries we need to deprecate google-token.

google-token consists in just one file with a class GoogleToken, the class is just handling the read of a credentials file and JWS auth. @gtoken is only used by @google-auth-library in jwtclient.

So we need to move it to auth.

Note: Npm dependent list don’t show big external customers using it directly, most of the use of it is through the auth library.