Integrate short-lived SSH certificates with GitHub SSH CA

I’d like to be able to use cloudflared access ssh-gen to then clone my GitHub (Enterprise Cloud) repositories using the SSH CA functionality.

To enable this work, the CA (Cloudflare) would need to add extensions to the SSH certificates. See https://docs.github.com/en/enterprise-cloud@latest/organizations/managing-git-access-to-your-organizations-repositories/about-ssh-certificate-authorities.