Updates the user image to the latest version of JupyterHub and brings with it new versions of conda etc. Some packages are removed because conda can't find versions that don't cause conflicts. Something to investigate for the next round.
The image is available as betatim/openhumans-singleuser:v8 from docker hub but we should rebuild it and push it to the OH docker account like the previous ones.
Updates the user image to the latest version of JupyterHub and brings with it new versions of conda etc. Some packages are removed because conda can't find versions that don't cause conflicts. Something to investigate for the next round.