Environment and notebook updates

[ktyle]

Also to diagnose cookbook and other Pythia-related build errors ProjectPythia/cookbook-template#160

[github-actions]

👋 Thanks for opening this PR! The Cookbook will be automatically built with GitHub Actions. To see the status of your deployment, click below.
🔍 Git commit SHA: c457092
✅ Deployment Preview URL: https://ProjectPythia.github.io/ERA5_interactive-cookbook/_preview/9

[brian-rose]

Yay that this cookbook is building again!

It would be great to leave a comment in the env file about why all these version pins are needed, especially if we can point to one or more upstream issues. I believe this was part of our draft Cookbook review guidelines, although we never finished formalizing those.

I'm afraid I've lost track of all the sphinx issues so I'm not sure what comments to add here.

[ktyle]

@brian-rose I've added some text in the environment file. This is still a very short-term solution, as the conda-forge dependencies with regard to pydata-sphinx-theme now require at least 0.8.0 for the environment, while the sphinx-pythia-theme requires 0.7.2. Fortunately, at least for now, installing sphnix-pythia-theme via pip downgrades pydata-sphinx-theme.

[brian-rose]

Great! That's helpful to note the specific version of sphinx-pythia-theme at issue. Hopefully we'll get back to a more sane dependency stack at some point.