Upgrade to latest JupyterBook version

[Ryan Abernathey]

We are currently pinned to version 0.5.2:

earth-env-data-science-book/.circleci/config.yml

Line 97 in a97d6c5

 - run: pip install --user nbconvert==5.6.1 jupyter-book==0.5.2 

JupyterBook is on 0.11.2. So we are very far behind.

We should upgrade to the latest version. This will likely break our CI.

Shamelessly cc'ing @choldgraf for any tips he might have.

[Chris Holdgraf]

Hmm - I'd start here https://github.com/executablebooks/jupyter-book/wiki/The-Jupyter-Book-Wiki#the-jupyter-book-legacy-upgrade-guide that is what folks were using back when the new build system was released!

[Chris Holdgraf]

lol #33 is a great title for a PR