UCA-252 Update Jupyterhub to version 0.9.4

Dockerfile

@@ -81,7 +81,7 @@ RUN curl -O https://bootstrap.pypa.io/get-pip.py && \
 
 RUN pip3 --no-cache-dir install \
             'notebook==5.7.4' \
-            'jupyterhub==0.8.1' \
+            'jupyterhub==0.9.4' \
             'jupyterlab==0.35.4' \
             'jupyter_nbextensions_configurator'