Feature: support for Github Merge Queue

[davidalbers]

I'm testing Github merge queue and the Mergeable app doesn't run for PRs in the merge queue.

For some background: PR branches in the merge queue are rebased with the main branch. Then required PR checks must pass again before the original PR actually gets merged into the main branch.

I assume the issue is either that the app doesn't handle merge_group hooks or that a separate branch is made for PRs in the merge queue. For reference this seems to be a common issue.

Is there a way to handle checks in the merge queue? I'm thinking of something like when: merge_group.* or just having checks from a merge group be marked a "pass" since they already passed in the PR.

Side note: merge queue is a beta feature. One of the top requested (but not yet implemented!) features is to require a separate set of checks in the queue. So an alternative could be to wait for that capability and then I would not include mergeable in the queue checks.

[shine2lay]

if they send over a webhook, you can add code to mergeable to be able to handle it. I suspect there will be a need to update permission in order to receive merge_group webhook events