Add PubkeyAuthOptions to gitlab-sshd
In order to enforce a touch requirement for ssh keys, we need to enable touch-required and verify-required which are openssh options currently.
https://man.openbsd.org/sshd_config.5#PubkeyAuthOptions
Since we need gitlab-ssh for ip filtering, and the additional logging is great, we would want to add the touch and verify flags so we can further secure ssh keys on yubikeys