Fix link for colab (#929)

Fix link to point to correct colab for ensembling example

Author: chauhang

notebooks/ensembling.ipynb

@@ -11,7 +11,7 @@
         "\n",
         "This example illustrates how to vectorize model ensembling using vmap.\n",
         "\n",
-        "<a href=\"https://colab.research.google.com/github/pytorch/functorch/blob/main/notebooks/colab/jacobians_hessians_colab.ipynb\">\n",
+        "<a href=\"https://colab.research.google.com/github/pytorch/functorch/blob/main/notebooks/colab/ensembling_colab.ipynb\">\n",
         "  <img style=\"width: auto\" src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/>\n",
         "</a>\n",
         "\n",
@@ -388,4 +388,4 @@
   },
   "nbformat": 4,
   "nbformat_minor": 5
-}
+}