Add column_name to protocol

dbt_semantic_interfaces/protocols/time_spine.py

@@ -1,7 +1,7 @@
 from __future__ import annotations
 
 from abc import abstractmethod
-from typing import Protocol, Sequence
+from typing import Optional, Protocol, Sequence
 
 from dbt_semantic_interfaces.implementations.node_relation import NodeRelation
 from dbt_semantic_interfaces.type_enums import TimeGranularity
@@ -57,3 +57,9 @@ class TimeSpineCustomGranularityColumn(Protocol):
     def name(self) -> str:
         """The column name."""
         pass
+
+    @property
+    @abstractmethod
+    def column_name(self) -> Optional[str]:
+        """The column name."""
+        pass