py version support policy, RHEL: only track full support releases

[mr-c]

Allow for any version of Python, not just the supported version

This would mean that we can then drop Python 3.6 support

[codecov]

Codecov Report

Merging #1881 (69b0c22) into main (2fedbd6) will increase coverage by 0.04%.
The diff coverage is 89.28%.

@@            Coverage Diff             @@
##             main    #1881      +/-   ##
==========================================
+ Coverage   83.87%   83.91%   +0.04%     
==========================================
  Files          46       46              
  Lines        8159     8150       -9     
  Branches     2224     2169      -55     
==========================================
- Hits         6843     6839       -4     
+ Misses        845      842       -3     
+ Partials      471      469       -2     

Files Changed	Coverage Δ
cwltool/command_line_tool.py	87.31% <ø> (ø)
cwltool/context.py	100.00% <ø> (ø)
cwltool/cwlrdf.py	29.06% <ø> (ø)
cwltool/docker.py	72.95% <ø> (ø)
cwltool/job.py	81.92% <ø> (ø)
cwltool/load_tool.py	87.03% <0.00%> (ø)
cwltool/software_requirements.py	72.97% <50.00%> (-0.37%)	⬇️
cwltool/utils.py	84.52% <90.00%> (+1.79%)	⬆️
cwltool/checker.py	96.87% <100.00%> (-0.03%)	⬇️
cwltool/cwlprov/__init__.py	92.00% <100.00%> (+0.95%)	⬆️
... and 2 more

... and 1 file with indirect coverage changes