Add ocean packages to pangeo-notebook

[TomAugspurger]

xref #28

[TomAugspurger]

cc @scottyhq & @jhamman.

[rabernat]

As soon as conda-forge/staged-recipes#11980 is merged, we can install this from conda.

[scottyhq]

/condalock

☝️ remember you need this comment to update lock files prior to building. fine by me to add these packages.

[scottyhq]

locking environment failed (https://github.com/pangeo-data/pangeo-docker-images/runs/797223398?check_suite_focus=true) because pip isn't supported by conda-lock (mariusvniekerk/conda-lock#4).

We got around this in the ml-notebook image by also including a sidecar requirements.txt. https://github.com/pangeo-data/pangeo-docker-images/blob/master/ml-notebook/requirements.txt

The base-image Dockerfile runs a pip install command after conda create:

pangeo-docker-images/base-image/Dockerfile

Line 117 in d4b3c1e

${NB_PYTHON_PREFIX}/bin/pip install --no-cache-dir -r requirements.txt \

[scottyhq]

/condalock

[TomAugspurger]

/condalock

[TomAugspurger]

@scottyhq fixed the merge conflicts (I was behind when I made my branch).