title: What is GitHub /.well-known/openid-configuration URL?
body: <p>I am trying to find it in the developer doc but no luck:
  <a href="https://developer.github.com/apps/building-oauth-apps/authorizing-oauth-apps/" rel="noreferrer">https://developer.github.com/apps/building-oauth-apps/authorizing-oauth-apps/</a></p>
  
  <p>Does GitHub expose a discovery endpoint for openid?</p>