Use google-auth rather than oauth2client

python3-oauth2client has been deprecated and unmaintained for several years. It's not compatible anymore with new version of pyopenssl. It has also been replaced with google-auth: https://google-auth.readthedocs.io/en/latest/oauth2client-deprecation.html

fence-agents makes the switch easy since it has dynamic support for both python3-google-auth and python3-oauthclient as visible in https://github.com/ClusterLabs/fence-agents/blob/main/agents/gce/fence_gce.py#L37-L40

The only need is to change dependencies so that google-auth (the prefered library) is available and it will be used.

Thanks to Adrien Nader.