Clear outputs (tensorflow#1292)

Author: MarkDaoust

docs/tutorials/avro.ipynb

@@ -138,16 +138,7 @@
       "metadata": {
         "id": "dX74RKfZ_TdF"
       },
-      "outputs": [
-        {
-          "name": "stdout",
-          "output_type": "stream",
-          "text": [
-            "tensorflow-io version: 0.17.0\n",
-            "tensorflow version: 2.4.0\n"
-          ]
-        }
-      ],
+      "outputs": [],
       "source": [
         "print(\"tensorflow-io version: {}\".format(tfio.__version__))\n",
         "print(\"tensorflow version: {}\".format(tf.__version__))"