Drop support for Python 3.9 and begin supporting 3.12
This is a bit opinionated so I don't consider it as a show stopper, but I highly encourage you to consider it.
cellpy depends on NumPy, and they will drop support for Python 3.9 in a month (Apr 4, 2024).
Adding support for Python 3.12 requires some work on the OtherPath object since it builds on pathlib that had a major upgrade going from Python 3.11 to Python 3.12. Should be implemented before v1.1.
Closing it for now - will reopen it soon when we start making the necessary changes in OtherPaths for supporting py3.12
Let's keep this open since it's due soon, but I'll approve it for JOSS review.