Add TODO

Signed-off-by: Felix Wang <wangfelix98@gmail.com>

Author: felixwang9817

sdk/python/feast/feature_store.py

@@ -1537,6 +1537,7 @@ def _get_columnar_entity_values(
     def _get_entity_maps(
         self, feature_views
     ) -> Tuple[Dict[str, str], Dict[str, ValueType], Set[str]]:
+        # TODO(felixwang9817): Support entities that have different types for different feature views.
         entities = self._list_entities(allow_cache=True, hide_dummy_entity=False)
         entity_name_to_join_key_map: Dict[str, str] = {}
         entity_type_map: Dict[str, ValueType] = {}