Updating .readthedocs.yml with Python3.11

[jaymedina]

The Astrocut RTD maintainers received an e-mail notification about adding a .readthedocs.yml v2 configuration file to our project, as they will no longer be supporting projects with implicit dependencies. More info can be found in this article: https://blog.readthedocs.com/migrate-configuration-v2/ .

@ceb8 already built us a .readthedocs.yml v2 file, so we are good to go. The reason we actually got that e-mail was because we had the following checkbox checked off in the Advanced Settings of the Astrocut project, which is the feature that will be deprecated in September 2023:

All it needed was to be updated to require python 3.8 instead of 3.7, because 3.7 does not jive with astropy>=5.2, which caused our documentation to break for the past 4 months, and is the actual reason for this PR:

TLDR; This PR updates the .readthedocs.yml to build documentation on python 3.8 (as opposed to the original 3.7), because our minimum astropy requirement of >=5.2 doesn't work with py37. This PR also updates the minimum python version requested in the setup.cfg.

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (367da13) 94.45% compared to head (60f80ea) 94.45%.
Report is 20 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main      #89   +/-   ##
=======================================
  Coverage   94.45%   94.45%           
=======================================
  Files           8        8           
  Lines        1443     1443           
=======================================
  Hits         1363     1363           
  Misses         80       80           

Files Changed	Coverage Δ
astrocut/__init__.py	91.66% <100.00%> (ø)
astrocut/cube_cut.py	98.97% <100.00%> (ø)
astrocut/cutouts.py	88.84% <100.00%> (ø)
astrocut/make_cube.py	94.15% <100.00%> (ø)

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[falkben]

Default python version for readthedocs is 3.11. 3.8 is going end of life next year. Let's just build the docs using 3.11 instead? It's also faster -- which I think is better for everyone.

Also -- we probably should be testing the package on 3.11, besides just the currently broken dev only dependencies. And we should probably start testing on 3.12 as well. These could be handled in a separate PR.

[falkben]

in addition to bumping RTD to 3.11, can we also update this to 3.8

https://github.com/spacetelescope/astrocut/blob/main/astrocut/__init__.py#L13

[falkben]

assuming docs are building, looks good to me