Setup a PR review bot

[guhitb]

Created a PR review bot. It does the following:

1. Marks new PRs with the bot-review label and sets it to draft status.
2. Checks to see if the PR contains the elements of a PR Template (from .github/pull_request_template.md).
3. If PR matches a template, it removes the bot-review label and removes the PR from draft status.

The bot determines if a template has been used by looking at the **bolded headings**. It checks each known template against the body of the pull request.

Editing the pull request body causes the PR review bot to run again.

Issue: #30715

[jnewb1]

do you have some examples of it working on your fork?

[guhitb]

Here are some examples.

No template found, PR failed

openpilot-.2.mp4

Template found, PR passed

openpilot-.4.mp4

PR is edited, status is updated

openpilot.mp4

[jnewb1]

does pygithub have an api for doing stuff like converting to draft, getting pull request id, etc?

[guhitb]

As far as I could discover, draft status cannot be be modified by the REST endpoint that PyGithub uses internally.

Only the GraphQL endpoint can convert a PR to and from a draft. The required pull request id can only be obtained through the GraphQL endpoint.

PyGithub only handles labels, I could remove it as a dependency and do everything through the GraphQL endpoint. What do you think?

[adeebshihadeh]

Thanks for the PR!

This is bigger and more custom than I was expecting. This is pretty generic stuff, and it's important that it has basically no maintenance cost (i.e. in the next year, we don't have to touch it to get it working again because some endpoint changed or something). Are there existing Actions we can use instead? The ideal thing is a single action, but perhaps there's a few different ones we can chain together. There's also github-script which I imagine would simplify this a bit.