Support puz v2 files with UTF-8 encoding
In 2021 puzpy introduced support for detecting and reading puz v2 files, which support UTF-8 as opposed to ISO-8859-1. However, a new release with this support has not been tagged or uploaded to PyPI, so we need to grab the latest source directly.
Unfortunately, flatpak-pip-generator doesn't support direct package URLs, so this has to be manually added to python3-requirements.json. If we want to hold off until there's a PyPI release so as to not create more maintainer work, that is understandable.
The current PyPI version 0.2.5 (2019) is equivalent to Git commit 6109ad5 (Fix Issue #21, 2019-06-07). puz v2 support was added in ae71d58 (add support for reading/writing utf-8 with v2 files (#26), 2021-06-02)