docs: show current duoauthproxy version in readme
docs: show current duoauthproxy version in readme

Remove references to old version.
We bumped to version 2.4.11 with commit c12896f19a9ad45.

jumanjihouse/docker-duoauthproxy,amacneil/docker-duoauthproxy,amacneil/docker-duoauthproxy,jumanjiman/docker-duoauthproxy