Shapely doesn't have a Windows wheel on pypi yet, but we can get them
from https://www.lfd.uci.edu/~gohlke/pythonlibs/#shapely. This unblocks
(and because wheels are matched to python versions, *requires*)
upgrading to Python 3.10.
This appears to be incompatible with pyinstaller. I get the following
when trying to run the executable generated with pyside6:
```
Traceback (most recent call last):
File "qt_ui\main.py", line 29, in <module>
File "PyInstaller\loader\pyimod03_importers.py", line 476, in exec_module
File "qt_ui\windows\QLiberationWindow.py", line 28, in <module>
File "PyInstaller\loader\pyimod03_importers.py", line 476, in exec_module
File "qt_ui\widgets\map\QLiberationMap.py", line 11, in <module>
ImportError: could not import module 'PySide6.QtPrintSupport'
```
py is a shortcut that launches the *latest* version of Python on the
machine. https://stackoverflow.com/a/50896577/632035
The build machines were updated to include python 3.9, so we were
doing everything with 3.9 instead of 3.8. pyproj doesn't have a binary
wheel for 3.9 on pypi yet, so we were falling back to building it from
source, which we aren't able to do, breaking the build.
