update data path

Author: gmanchon

content/airbnb-challenge.ipynb

@@ -1413,8 +1413,7 @@
     "\n",
     "\n",
     "```pandas\n",
-    "import urllib\n",
-    "i = urllib.request.urlopen('data/Neighbourhoods_New_York_City_Map.PNG')\n",
+    "i = 'data/Neighbourhoods_New_York_City_Map.png'\n",
     "plt.imshow(plt.imread(i), zorder=0, extent=[-74.258, -73.7, 40.49, 40.92])\n",
     "ax = plt.gca()\n",
     "affordable_df.plot(\n",