`Repository.__init__` (possibly others) missing `os.PathLike` typing

[warriorstar-orion]

Support for PathLikes was added in https://github.com/libgit2/pygit2/pull/990. However, it doesn't appear the typing for some of the affected methods were updated. Repository.__init__ was the one I caught, but there may be more (which is why this isn't just a PR, I didn't want to make this one change and end up missing others).

https://github.com/libgit2/pygit2/blob/5b27dee1162124a4021d6aa81f4d6ba78dee9f04/pygit2/repository.py#L1523-L1528