Support GHES

[nicola-lunghi]

The Github authentication plugin allows to connect to priate instances of github enterprise
Please add a configuration field to allow to use private github instances

Thanks!

[thedaviddias]

@cschleiden any ETA or status on when this could be possible?

[cschleiden]

@thedaviddias No updates to share at this point, we are still figuring out the next set of priorities.

[thedaviddias]

Thank you @cschleiden!

[jeffstoner]

I'm about to on-board 300+ developers to GHES and would love to tell them "you can use this extension to mind your Actions activities directly in VSCode."

[megamorf]

I'm member of a 20000+ user GHES instance and would also love to see some prioritization of this ticket.

[Olfi01]

This would also require a tiny change to the language server, which I proposed in actions/languageservices#43, to actually show all the relevant information

[Olfi01]

I implemented the necessary changes in #183, would be happy if someone could review 😄