fix: Fixed import os in Jupyter example

Author: Alan Christie

examples/JobChain.ipynb

@@ -39,6 +39,7 @@
    "source": [
     "# To run Jobs using the API we need our \"Project\".\n",
     "# This is set for us by the Data Manager using an environment variable.\n",
+    "import os\n",
     "project = os.environ[\"DM_PROJECT_ID\"]"
    ]
   },
@@ -52,7 +53,6 @@
     "# The file is written for us by the Data Manager and is written to a\n",
     "# '.squonk2' directory in the project root. The environment is given\n",
     "# the name \"current\" (which we'll refer to later).\n",
-    "import os\n",
     "os.environ[\"SQUONK2_ENVIRONMENTS_FILE\"] = \".squonk2/environments\""
    ]
   },