Make it so that plasmapy.__version__ uses current date in editable installs

[namurphy]

Currently when we do an editable install of a development version of PlasmaPy (i.e., with pip install -e .), it gives us something like:

>>> import plasmapy
>>> plasmapy.__version__
'2023.1.1.dev943+gb1495a48'

I'm not sure why, but it's giving us last year. We should update it so that it gives something like 2024.4.12.dev943+gb1495a48 when the day is (or the last commit was on) 2024 Apr 12. The last part of it should be the git hash, essentially the same way that it is done now. I'm not sure if we can use setuptools_scm for this, but it's worth looking into.