Upgrade RTD to Ubuntu 24 and miniforge

[djhoese]

• Closes #xxxx
• Tests added
• Tests passed: Passes pytest pyspectral
• Passes flake8 pyspectral
• Fully documented
• Add your name to AUTHORS.md if not there already

[adybbroe]

LGTM

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.17%. Comparing base (cb6834b) to head (097aaeb).
⚠️ Report is 5 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #280   +/-   ##
=======================================
  Coverage   91.17%   91.17%           
=======================================
  Files          25       25           
  Lines        2673     2673           
=======================================
  Hits         2437     2437           
  Misses        236      236           

Flag	Coverage Δ
unittests	91.17% <ø> (ø)

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