Fix Themes example to use new default index name

Signed-off-by: Itay Dafna <[email protected]>

Author: ibdafna

examples/Themes.ipynb

@@ -178,7 +178,7 @@
     "    text_color=\"white\",\n",
     ")\n",
     "g.renderers = {\n",
-    "    \"index\": grid.TextRenderer(\n",
+    "    \"key\": grid.TextRenderer(\n",
     "        background_color=grid.VegaExpr(\n",
     "            \"cell.row % 2 === 0 ? 'rgb(21, 116, 163)': 'rgb(21, 116, 163)'\"\n",
     "        ),\n",
@@ -190,7 +190,7 @@
  ],
  "metadata": {
   "kernelspec": {
-   "display_name": "Python 3",
+   "display_name": "Python 3 (ipykernel)",
    "language": "python",
    "name": "python3"
   },
@@ -204,7 +204,7 @@
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
-   "version": "3.9.5"
+   "version": "3.8.11"
   }
  },
  "nbformat": 4,