Make Issue Forms available for Pull Requests

[airtonix]

simple enough first goal: 1:1 what we get in issue forms for issues.

second goal: allow us to use github action expressions and context to compute resulting pull request form.

[thibaudcolas]

Concurring this would be pretty cool! A very basic use case for us would be to have a field that prompts pull request authors to enter the issue number their pull request is about, if any.

And then, similarly to the official docs for issue forms, having a prompt for people to select which browsers a pull request has been tested in.

[DNin01]

I think this would help a lot in creating task lists or to require information like what issue is being resolved.

[k-doering-NOAA]

This would be really helpful for the teams I work on! It would be a lot easier for the submitter to see what information should be included (and not opt out of parts of the pull request template).

[migbash]

This would be amazing!