Add git-checkout-pr feature

[yakov116]

1. LINKED ISSUES:
   Closes Can RG recommend me the command to fetch a PR locally? #2767

2. TEST URLS:
   Remote URL: Mark peer dependencies as optional twbs/bootstrap#30329
   Upstream URL: karma: stop excluding polyfill.js from istanbul twbs/bootstrap#30740
   Own PR: undefined
   Local PR: I and I am collaborator, I removed the exclude for merged PR from it. You can probably find a PR since you are a collaborator in more repositories then me :).

3. SCREENSHOT:
   

[yakov116]

Draft until after lint PR is merged

[yakov116]

All working with isLocalPR dropped
I tested on this PR (My own)
webpack/webpack#11831
webpack/webpack#11824

I don't have a collaborator with a local PR to test on (but I manually tested on a merged and it worked)

[fregante]

I think the logic is fine now, but I haven’t tested all the cases. Can you test them and include your testing links? (Of course they’ll be related to you as the viewer)

[yakov116]

I think the logic is fine now, but I haven’t tested all the cases. Can you test them and include your testing links? (Of course they’ll be related to you as the viewer)

I tested them all. I keep posting links but they keep getting merged 😿 .

[fregante]

What I do is find old PRs on large, famous repos so there’s no chance that they get merged quickly.

[yakov116]

What I do is find old PRs on large, famous repos so there’s no chance that they get merged quickly.

Like octoicon 😆 ?

[yakov116]

Remote URL: twbs/bootstrap#30329
Upstream URL: twbs/bootstrap#30740
Own PR: undefined
Local PR: I and I am collaborator, I removed the exclude for merged PR from it. You can probably find a PR since you are a collaborator in more repositories then me :).

[yakov116]

@fregante do you mind to review? It would be great to have this ship tomorrow!

[yakov116]

@fregante now is the perfect time to review this as we both have PR's open (from local branchs)

[fregante]

I'll extract the remote logic here because the review comment is easily lost:

It's kinda complicated and needs a little guessing, actually. Examples:

• as a collaborator of this repo, origin points to this repo
• you're also a collaborator of this repo, but I don't think that origin points to this repo yet since you still open

In short, if I see a PR opened from a branch here, I can pull origin, but if you see it, you will pull upstream, I'm guessing.

I think it varies based on the viewer and on the head repo:

viewer ⬇️	head: viewer’s own repo	head: owner’s repo	head: other repo
owner	origin		$author
collaborator	origin	origin or upstream	$author
3rd party	origin	origin or upstream	$author

Notes:

• there are 2 "or"s, but I crossed the less likely one; we can probably use the other option in our logic
• when it's origin, there shouldn't be a git remote add