Fix path to Colab (#547)

The current path is the one generated by Colab export but does not match the location of the notebook.

Signed-off-by: Mihai Maruseac <[email protected]>

Author: mihaimaruseac

docs/demo.ipynb

@@ -7,7 +7,7 @@
         "colab_type": "text"
       },
       "source": [
-        "<a href=\"https://colab.research.google.com/github/mihaimaruseac/model-transparency/blob/main/Model_signing_with_%60model_signing%60_v1_0.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
+        "<a href=\"https://colab.research.google.com/github/sigstore/model-transparency/blob/main/docs/demo.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
       ]
     },
     {
@@ -1234,4 +1234,4 @@
   },
   "nbformat": 4,
   "nbformat_minor": 0
-}
+}