- converted tool.poetry to PEP 621 (default behavior for poetry)
- converted setup.py to PEP 621 (recommended by setuptools)
- use pyproject.toml instead of version.txt
- use importlib instead of version.txt
- use PEP 621 dependency format in flatpak build scripts
- added tomli as a dev dependency (used in build scripts)
- removed version.txt (no longer used)
- cleaned up dependencies
- version is still in desktop/setup.py (unclear on how snapcraft uses it)
- poetry lockfiles need to be rebuilt