Repository.create_note() does not accept bytes

Hi,

Thank you for pygit2! I'm using it heavily in a project to present all Ubuntu source package history as git repositories.

Any chance Repository.create_note() could be adjusted to accept bytes as well as str? An issue I just hit is when I'm trying to create git notes that contain text that is not UTF-8 encoded. This happened historically in Debian/Ubuntu packaging history and I'd like to represent that in git notes that get created by just "passing through" the unknown encoding. As git doesn't care about the encoding of a note, I think this should work OK.

The relevant code is here: https://github.com/libgit2/pygit2/blob/58da6bb2b958139dab285e183ca6616509960587/src/repository.c#L1677

It looks like this could just be tweaked slightly to also accept a bytes, as it's all being converted into a C-string to hand to git anyway. There might be an edge case to consider when the bytes contains NULs. That might have to be unacceptable, tested for and result in a ValueError. It might also make sense to adjust behaviour everywhere pygit2 accepts a string to hand to git, so I appreciate it's a bit of a rabbit hole.

This isn't essential so I can work around this and don't want to get into testing a patch right now, but I thought it might be worth noting this in your issue tracker (and I can now link to this from my workaround).

Bắt đầu tại src/repository.c, xung quanh Repository.create_note() ở dòng 1677, và kiểm tra cách thông báo ghi chú được chuyển đổi trước khi truyền cho Git. Công việc hoàn tất khi bytes được chấp nhận cùng với str đối với nội dung ghi chú không phải UTF-8, với kết quả được xác định cho các byte NUL được nhúng, chẳng hạn như từ chối chúng bằng ValueError.