Python 3.14 support

[moreati]

Beta expected May 2025, final expected Oct 2025 https://peps.python.org/pep-0745/

From https://docs.python.org/3.14/whatsnew/3.14.html

• os: Soft deprecate os.popen() and os.spawn* functions. They should no longer be used to write new code. The subprocess module is recommended instead. (Contributed by Victor Stinner in gh-120743.)

• The import system:

  • Setting cached on a module while failing to set spec.cached is deprecated. In Python 3.15, cached will cease to be set or take into consideration by the import system or standard library. (gh-97879)

  • Setting package on a module while failing to set spec.parent is deprecated. In Python 3.15, package will cease to be set or take into consideration by the import system or standard library. (gh-97879)