Fixed jupyter upgrade to upgrade to 5.* and not 6.*

nthiery · nthiery · commit 0cf7116b77df · 2017-10-17T07:46:32.000Z
diff --git a/Dockerfile b/Dockerfile
@@ -13,4 +13,4 @@ RUN chown -R ${NB_USER}:${NB_USER} ${HOME}
 USER ${NB_USER}
 
 # Upgrade to jupyter 5.* as required by mybinder
-RUN sage -pip install --upgrade notebook
+RUN sage -pip install --upgrade "notebook>=5"
