feat: Add metadata as parameter to TaskUpdater.update_status()

Author: holtskinner

src/a2a/server/tasks/task_updater.py

@@ -49,6 +49,7 @@ async def update_status(
         message: Message | None = None,
         final: bool = False,
         timestamp: str | None = None,
+        metadata: dict[str, Any] | None = None,
     ) -> None:
         """Updates the status of the task and publishes a `TaskStatusUpdateEvent`.
 
@@ -77,6 +78,7 @@ async def update_status(
                     task_id=self.task_id,
                     context_id=self.context_id,
                     final=final,
+                    metadata=metadata,
                     status=TaskStatus(
                         state=state,
                         message=message,