/tg/Station 13

We've merged N3X15's new .yml changelog system from /vg/.
Check the guide on the wiki to see how to use it, if you're confused ask for help in #coderbus.

Things I've figured out so far:

1. You newly created .yml will be unversioned, don't be a dork like me and forget to tick it when committing your changes
2. Retroactively adding your .yml changelog file to pre-existing PRs will work provided you don't stuff up the branch update
3. The PR-#### stuff is only needed if you're going to have multiple PRs with changelogs in them open at a time.
4. If you do that you'll need to have "delete-after: True" in it, but otherwise if you want yours to stay there once merged you can leave that out.