Add support for SSH certificates

[adontz]

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/6/html/deployment_guide/sec-using_openssh_certificate_authentication https://smallstep.com/blog/use-ssh-certificates/ https://www.vaultproject.io/docs/secrets/ssh/signed-ssh-certificates

[kzshantonu]

+1

[aderumier]

+1 for this,

it can be used with smallstep step-ca, to generate ssh certificate with oidc .

https://smallstep.com/blog/diy-single-sign-on-for-ssh/

[csudderth]

Would love to +1 this. Support for Warp to use a short lived SSH cert as opposed to distributing its SSH keys would be huge.