Clean up CI

[blink1073]

• Use more things from maintainer_tools -> base setup, minimum version test
• Test an installed sdist
• Clean up python and other dependencies

[codecov-commenter]

Codecov Report

❗ No coverage uploaded for pull request base (main@819dce5). Click here to learn what that means.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main     #241   +/-   ##
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  Coverage        ?   68.40%           
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  Files           ?       19           
  Lines           ?     1570           
  Branches        ?        0           
=======================================
  Hits            ?     1074           
  Misses          ?      496           
  Partials        ?        0           

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