Add dask as dependency

Realized that it's not listed as a dependency even though it was being used in some of the code. This is needed when creating the environments for each proposal.

(On that note, one can now use scs-create-toolbox-env --proposal <PROPOSAL> to generate the environment.)

@lleguy @mercadil

setup.py

@@ -10,7 +10,7 @@ with open('VERSION') as f:
 
 basic_analysis_reqs = ['numpy', 'scipy',]  # and is readily available in Karabo
 advanced_analysis_reqs = [
-    'pandas', 'imageio', 'xarray>=0.13.0', 'h5py', 'h5netcdf',]
+    'pandas', 'imageio', 'xarray>=0.13.0', 'psutil', 'h5py', 'h5netcdf',]
 interactive_reqs = ['ipykernel', 'matplotlib', 'tqdm',]
 maxwell_reqs = ['joblib', 'papermill', 'dask',
                 'extra_data', 'euxfel_bunch_pattern>=0.6']