Support new issue types

[Haarolean]

Github introduced new enhancements to issues: issue types, sub-issues, and other minor issues. It seems like they're forcing these issue types by default now, the field is visible even if you don't want to use it, my guess is it will be a default soon.
So it makes sense to implement this kind of API.

https://github.blog/changelog/2025-01-13-evolving-github-issues-public-preview/
While it's stated that it's in "preview", they've already started rolling it out actively without opting in.