Allow for GitHub teams as reviewers

[xendk]

GitHub allows for requesting review from an organization team, which is a way to ask for review from anyone in a group. We have a bot that picks up on this and posts a message to our Zulip chat.

But it doesn't seem to work in forge. If I manually type out reload/developers, and press return an extra time to confirm it, forge seems to have accepted it and done something, but it doesn't show up on the PR.

[danomeerf]

I second this request as our standard practice (with GitHub) is to set as Reviewers a list of people maintained in the group <organization>/pull-request-reviewers. As it stands now I either have to add them individually in Forge from memory (not that the list changes that often) or browse to the PR in GitHub and set the group there. Entering the group name in Forge seems to do nothing and no error is indicated.

[chemmi]

Same. It would be great to assign Github teams for review.