Set allow_errors: False

[brian-rose]

Addresses ProjectPythia/cookbook-template#53

[brian-rose]

This should cause CI failure since these notebooks do not execute due to data access problems.

[github-actions]

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[brian-rose]

Here I see a new problem. The notebook execution DID fail, e.g. these lines in build log. But CI passed.

The reason is probably because we still have execute_notebooks: cache instead of force.

[brian-rose]

Actually it turns out that jupyter-book build does NOT normally raise exceptions when notebook execution fails, instead raises warnings. So there's a fundamental flaw in our CI testing strategy!

Some info about this here: https://github.com/orgs/executablebooks/discussions/892#discussioncomment-4348868

[brian-rose]

We eventually addressed this problem by putting

sphinx:
  config:
    nb_execution_raise_on_error: true # raise exception in build if there are notebook errors (this flag is ignored if building on binder)

in the _config file.

This repo needs this plus quite a few other updates to bring it up to speed with the latest cookbook template.