fix python compatibility

Author: themisvaltinos

sqlmesh_dbt/error.py

@@ -30,7 +30,7 @@ def wrapper(*args: t.List[t.Any], **kwargs: t.Any) -> t.Any:
 
 
 class ErrorHandlingGroup(click.Group):
-    def add_command(self, cmd: click.Command, name: str | None = None) -> None:
+    def add_command(self, cmd: click.Command, name: t.Optional[str] = None) -> None:
         if cmd.callback:
             cmd.callback = cli_global_error_handler(cmd.callback)
         super().add_command(cmd, name=name)