buku 2.7
========
- [x] Have you followed the [guidelines for contributing](https://github.com/Homebrew/homebrew-core/blob/master/CONTRIBUTING.md)?
- [x] Have you checked that there aren't other open [pull requests](https://github.com/Homebrew/homebrew-core/pulls) for the same formula update/change?
- [x] Have you built your formula locally with `brew install --build-from-source <formula>`, where `<formula>` is the name of the formula you're submitting?
- [x] Does your build pass `brew audit --strict <formula>` (after doing `brew install <formula>`)?
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- Respond to structural change in v2.7 (`buku` => `buku.py`);
- Refresh resources, including new deps `requests` and `urllib3`;
- Expand tests a little bit to test the new deps.
Updating resources is hell. I'll try to teach poet to read requirements.txt when I have time.
@ilovezfs The official download link (from announcement) is ftp://alpha.gnu.org/gnu/emacs/pretest/emacs-25.1.90.tar.xz, and I don't think https://alpha.gnu.org/gnu/emacs/pretest/ ever worked. So: it's kinda stupid, but nothing was promised in the first place.