URL with repo

sIts difficult to share githeartissues with people.

Visiting https://githeartissues.com/open-austin/open-austin.org should just work.

This also makes it easier to use githeartissues in multiple places. Open Austin is using it for:
- https://github.com/open-austin/iced-coffee
- https://github.com/open-austin/open-austin.org
