PR label automation

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**Discussion**
So its nice to have the new review progress and all but one thing that is bugging me is manually adding and removing labels.

The main labels im talking about are:
waiting for review
changes requested
merge conflicts / rebase needed
WIP

It would be nice to have some automation in it.

So if a PR is just created it gets the label Ready to review.

When somebody request some changes, the ready to review label gets removed and the changes requested label gets added. When the requested changes are resolved the label gets removed and waiting for review gets added.

When there are merge conflicts, the merge conflicts get added and when the conflicts are resolved the ready to review label gets added and merge conflicts label will be removed.

WIP will get added when there are allot of discussions going on within the PR about how to implement it. Example PR's are: #1083, #1095, #1262, #1281. Not sure how we would measure this though. Amount of comments or the body of a few huge comments or some sort of combination. We could maybe label a PR with WIP if it still receives allot of commits. Or if the PR title or descriptions mentions that it is a WIP, it detects that and adds a WIP label. Example PR https://github.com/FreeTubeApp/FreeTube/pull/1115. Oh and obviously draft PR's can be marked WIP and when they are not a draft anymore add ready to review and remove WIP.

The only label that cant be removed after merge in my opinion is dependencies because its related to the dependabot and a the only label that's worth something after merge. For example a ready to review label hold no value after merge but depenencies label does holds it value because its important to filter them quick if something goes wrong (*couch* electron).

This should make the review process easier because we can focus better and prioritize what PR's we should review and shouldn't review.

Some potentially useful links:
https://github.com/Matticusau/pr-helper

https://github.com/prince-chrismc/label-merge-conflicts-action
https://github.com/eps1lon/actions-label-merge-conflict

Edit: forgot to mention that labels have to be removed after PR is merged.