use jupyter_sphinx v0.2.0 from conda instead of my branch

[basnijholt]

This again needs #169. However, I have manually executed those commands from the CI.

See https://adaptive.readthedocs.io/en/test_documentation/ when the build finished.

[akhmerov]

Let's pin jupyter-sphinx at <= 0.3, and specify the thebe config like here. Pointing to this repo should be all it takes.

[basnijholt]

Actually, I rather pin it to a fixed version like everything else.

Is adding those lines to the config really enough to install thebelab?

Of course, it would need some buttons.

[basnijholt]

Also, how would we make sure that this gets executed https://github.com/python-adaptive/adaptive/blame/master/docs/source/tutorial/tutorial.Learner1D.rst#L13-L21

[akhmerov]

Also, how would we make sure that this gets executed https://github.com/python-adaptive/adaptive/blame/master/docs/source/tutorial/tutorial.Learner1D.rst#L13-L21

These will become visible but the user will need to manually execute those.

[jbweston]

I updated the dependency to jupyter_sphinx 0.2.1. All the other dependencies are pinned at exact version, so I think it's fine

[jbweston]

This LGTM