Add TensorFlow version.

PiperOrigin-RevId: 555270464

Author: MarkDaoust

site/en/guide/saved_model.ipynb

@@ -731,6 +731,8 @@
       "source": [
         "## Proto-splitting\n",
         "\n",
+        "Note: This feature will be part of the TensorFlow 2.15 release. It is currently available in the nightly build which you cqan install with `pip install tf-nightly`.\n",
+        "\n",
         "Due to limits of the protobuf implementation, proto sizes cannot exceed 2GB. This can lead to the following errors when attempting to save very large models:\n",
         "\n",
         "```\n",