cwltool Python support policy

[tetron]

Added "Python version support policy" page to documentation.

[codecov]

Codecov Report

Merging #1621 (eacecea) into main (0f70992) will decrease coverage by 0.09%.
The diff coverage is n/a.

❗ Current head eacecea differs from pull request most recent head 058ac67. Consider uploading reports for the commit 058ac67 to get more accurate results

@@            Coverage Diff             @@
##             main    #1621      +/-   ##
==========================================
- Coverage   66.82%   66.73%   -0.10%     
==========================================
  Files          93       93              
  Lines       16578    16583       +5     
  Branches     4404     4398       -6     
==========================================
- Hits        11078    11066      -12     
- Misses       4361     4379      +18     
+ Partials     1139     1138       -1     

Impacted Files	Coverage Δ
cwltool/cuda.py	35.29% <0.00%> (-39.71%)	⬇️
cwltool/argparser.py	91.63% <0.00%> (-2.91%)	⬇️
cwltool/cwltool/cuda.py	20.58% <0.00%> (-1.29%)	⬇️
cwltool/job.py	78.65% <0.00%> (-1.23%)	⬇️
cwltool/command_line_tool.py	77.19% <0.00%> (-0.28%)	⬇️
cwltool/main.py	71.71% <0.00%> (-0.27%)	⬇️
cwltool/docker.py	71.36% <0.00%> (-0.18%)	⬇️
cwltool/process.py	88.78% <0.00%> (-0.16%)	⬇️
cwltool/cwltool/context.py	88.41% <0.00%> (-0.08%)	⬇️
cwltool/checker.py	86.32% <0.00%> (-0.06%)	⬇️
... and 16 more

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[tetron]

@DailyDreaming @audrium @GlassOfWhiskey @michael-kotliar @johnbradley

https://github.com/common-workflow-language/cwltool/blob/b4a08a7cdcbf8ca86324b2baa21f507947d681e2/docs/pythonversions.rst

Proposed policy for when support for older Python versions will be dropped from cwltool. Thoughts? If you approve please respond with a thumbs up.

[mr-c]

the next Debian release will have Python 3.10 as the default