Need nb_conda package for Jupyter notebook to work within env

[taldcroft]

If ska3 is installed as an env instead of the root, then jupyter notebook ends up using the root Python for the kernel and nothing works. See jupyter/notebook#3311 (comment) and subsequent comments for the resolution. Installing it did the trick for me.

This brings in many more packages, and praying that it all works with our pinning.

[jeanconn]

Awesome. Thanks for finding this. I've been trying to do more testing with a sparse root (which is not our production/operational strategy) to test the "is ska3-core the minimal set" but obviously haven't found everything yet.