Use regular jupyterhub-singleuser for datahub
Use regular jupyterhub-singleuser for datahub

Special startup command can be removed for other hubs
once they all upgrade their JupyterLab versions

Ref #1468

ryanlovett/datahub,berkeley-dsep-infra/datahub,ryanlovett/datahub,berkeley-dsep-infra/datahub,berkeley-dsep-infra/datahub,ryanlovett/datahub