Python 3.8 compatibility (such as for Windows 7)

[Poikilos]

This is a redo of the pull request. The previous pull request had 0 commits since I rebased. The commits were stored in this branch:

git switch main
# At this point, slicked GitHub "Sync fork" button on web
git pull
git branch -b python-3.8-compat
git cherry-pick 6d6b15f2c3361050a1776d1f14fcca9e7163c577
git cherry-pick 7ed5549b87d83fed5e5a4957d5e400c195b76c25
# These changes were rehashed by git into python-3.8-compat (based on the new upstream main) as 0ed45f0 and 192a9a1 

so this one can be used for the PR.

To reiterate https://github.com/bobjacobsen/PythonOlcbNode/pull/23:

Python 3.8 compatibility changes:

• Match statements are changed to if-elif-else
  • in (some_value, some_other_value) is used to match against multiple values (instead of match's context-specific parsing of | as logical op which is used as binary op when not in a match scope)
• Python version requirement in pyproject is changed from >= 3.10 to >= 3.8
• May work on earlier versions of Python.
• May work on earlier versions of Windows such as Vista (not tested).
  • However, Python 3.7 backport to XP may have "problems with some Internet stuff" (https://retrosystemsrevival.blogspot.com/2021/01/python-371-for-windows-xp.html).

[bobjacobsen]

Thanks for this!