Switch away from unmaintained unbuildable `leven` package dependency

[flying-sheep]

leven doesn’t build with Python 3.11+, and Python 3.10 hasn’t been supported by the scientific Python world for a while. I’d generally avoid compiled dependencies that don’t ship wheels, they’re generally unreliable.

For alternatives, e.g. this one seems to be maintained: https://pypi.org/project/Levenshtein/