Oliver Hamlet e670605700 Fix building docs in CI ...

Older versions of Sphinx don't work with whatever the default version of
Python is on GitHub Actions, and never versions of Sphinx need a newer
version of Python.

Also update the RTD theme and Breathe while I'm at it.

2021-11-13 17:15:31 +00:00

..

workflows

Fix building docs in CI

2021-11-13 17:15:31 +00:00