Add __getattr__ to task decorator stub (#39425)

diff --git a/airflow/decorators/__init__.pyi b/airflow/decorators/__init__.pyi
index e88a535..5f566da 100644
--- a/airflow/decorators/__init__.pyi
+++ b/airflow/decorators/__init__.pyi
@@ -755,6 +755,7 @@
         """
     @overload
     def bash(self, python_callable: Callable[FParams, FReturn]) -> Task[FParams, FReturn]: ...
+    def __getattr__(self, name: str) -> TaskDecorator: ...
 
 task: TaskDecoratorCollection
 setup: Callable