Add an option to filter PR search by passing/failing/running CI checks #1806

When a project has many open pull requests, just finding one which is ready for review can be tricky. For example, pytest and matplotlib would both find this useful, along with smaller projects. Terrible mockup:

I know I'd love to be able to filter down to just the PRs with passing tests to review, or tests+approval to merge, or ... You get the idea. No idea why this doesn't already exist, so Refined Github seemed the place to suggest it 😄