bump notebook tag

Author: minrk

.env

@@ -15,7 +15,7 @@ DOCKER_MACHINE_NAME=jupyterhub
 DOCKER_NETWORK_NAME=jupyterhub-network
 
 # Single-user Jupyter Notebook server container image
-DOCKER_NOTEBOOK_IMAGE=jupyter/scipy-notebook:bb222f49222e
+DOCKER_NOTEBOOK_IMAGE=jupyter/scipy-notebook:8f56e3c47fec
 
 # Notebook directory in the container.
 # This will be /home/jovyan/work if the default