Added version tag to datasciecne-notebook-version

The latest version of datascience-notebook seem to be incompatible with the jupyterhub version, we are using right now. This fixes the version via image tag in the tools.json.

tools.json

@@ -2,7 +2,7 @@
     "jupyter": {
         "short_description": "Basic jupyter run with an empty notebook or on given notebook file.",
         "description": "### **Jupyter Notebook**: The Classic Notebook Interface\n\nThe Jupyter Notebook is the original web application for creating and sharing computational documents. It offers a simple, streamlined, document-centric experience.",
-        "image": "jupyter/datascience-notebook",
+        "image": "jupyter/datascience-notebook:lab-3.6.2",
         "path_prefix": "tree",
         "mount_path": "/home/jovyan",
         "icon": "jupyter_logo.svg",