CI bump to Python 3.10 for macOS

[DougBurke]

This is to test out https://discuss.python.org/t/pip-install-e-on-macos-suddenly-builds-for-universal2-by-default/16890/18 and is not intended for merging

I didn't update the XSPEC version as I don't know what versions are available on the mac channel.

[codecov]

Codecov Report

Merging #1541 (34e4549) into main (669bf0b) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1541      +/-   ##
==========================================
+ Coverage   78.95%   78.98%   +0.02%     
==========================================
  Files          72       72              
  Lines       26676    26676              
  Branches     4496     4511      +15     
==========================================
+ Hits        21063    21070       +7     
+ Misses       5420     5406      -14     
- Partials      193      200       +7     

Impacted Files	Coverage Δ
sherpa/__init__.py	40.07% <0.00%> (ø)
sherpa/astro/io/crates_backend.py	0.00% <0.00%> (ø)
sherpa/ui/utils.py	90.85% <0.00%> (+0.05%)	⬆️
sherpa/plot/pylab_backend.py	92.17% <0.00%> (+0.35%)	⬆️
sherpa/_version.py	31.42% <0.00%> (+1.42%)	⬆️

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[DougBurke]

Rebased as #1329 has been merged. I expect conda runs to fail because of known issues

[DougBurke]

Rebased after merging #1329 just to check

[DougBurke]

Closing as we now have #1563