Jinja ->v3.1

[ryancoe]

Jinja released v3.1.0 earlier today and it seems to create a build error for us related to including the Jupiter notebooks in the docs. The error message is module 'jinja2.utils' has no attribute 'escape'

2022-03-24T18:58:04.7554931Z ##[group]Run cd docs
2022-03-24T18:58:04.7555234Z �[36;1mcd docs�[0m
2022-03-24T18:58:04.7555488Z �[36;1mmake clean html�[0m
2022-03-24T18:58:04.7555746Z �[36;1mmake clean linkcheck�[0m
2022-03-24T18:58:04.7556005Z �[36;1mcd ../�[0m
2022-03-24T18:58:04.7610494Z shell: /usr/bin/bash -l {0}
2022-03-24T18:58:04.7610765Z env:
2022-03-24T18:58:04.7611049Z   CONDA_PKGS_DIR: /home/runner/conda_pkgs_dir
2022-03-24T18:58:04.7611326Z ##[endgroup]
2022-03-24T18:58:05.1157908Z python "source"/make_theory_animations.py
2022-03-24T18:58:17.4931774Z Running Sphinx v4.4.0
2022-03-24T18:58:20.3663321Z Copy example notebooks into docs/_examples
2022-03-24T18:58:20.3664236Z checking bibtex cache... out of date
2022-03-24T18:58:20.3694141Z parsing bibtex file /home/runner/work/WecOptTool/WecOptTool/docs/source/wecopttool_refs.bib... parsed 5 entries
2022-03-24T18:58:20.3950536Z building [mo]: targets for 0 po files that are out of date
2022-03-24T18:58:20.3968916Z building [html]: targets for 11 source files that are out of date
2022-03-24T18:58:20.3974478Z updating environment: [new config] 11 added, 0 changed, 0 removed
2022-03-24T18:58:20.3976429Z reading sources... [  9%] _examples/tutorial_1_wavebot
2022-03-24T18:58:20.9802350Z 
2022-03-24T18:58:20.9802956Z Notebook error:
2022-03-24T18:58:20.9803629Z AttributeError in _examples/tutorial_1_wavebot.ipynb:
2022-03-24T18:58:20.9804809Z module 'jinja2.utils' has no attribute 'escape'
2022-03-24T18:58:21.4410306Z make: *** [Makefile:22: html] Error 2
2022-03-24T18:58:21.4429650Z ##[error]Process completed with exit code 2.

[ryancoe]

Looks like the problem is actually from nbconvert: jupyter/nbconvert#1736

With cddd847 in #78, I have forced jinja2<3.1. Once jupyter updates nbconvert, we can remove this.