Update preprocessing_layers.ipynb

bug fix
ValueError: Multi-dimensional indexing (e.g. `obj[:, None]`) is no longer supported. Convert to a numpy array before indexing instead.

site/en/tutorials/structured_data/preprocessing_layers.ipynb

@@ -297,7 +297,7 @@
         "def df_to_dataset(dataframe, shuffle=True, batch_size=32):\n",
         "  df = dataframe.copy()\n",
         "  labels = df.pop('target')\n",
-        "  df = {key: value[:,tf.newaxis] for key, value in dataframe.items()}\n",
+        "  df = {key: value.to_numpy()[:,tf.newaxis] for key, value in dataframe.items()}\n",
         "  ds = tf.data.Dataset.from_tensor_slices((dict(df), labels))\n",
         "  if shuffle:\n",
         "    ds = ds.shuffle(buffer_size=len(dataframe))\n",