Update versions of packages used by RTD build workflow

[christopher-wild]

It appears the latest docs PR introduces features that are only compatible with sphinx-autoapi >= 3.0.0.

This PR updates the requirements file that ReadTheDocs uses to do it's build of the docs.

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	black	26		0	0.98s
✅ PYTHON	pylint	26		0	5.05s

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (718562f) 95.32% compared to head (953b9d0) 95.32%.
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #253   +/-   ##
=======================================
  Coverage   95.32%   95.32%           
=======================================
  Files          20       20           
  Lines        1411     1411           
=======================================
  Hits         1345     1345           
  Misses         66       66           

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