Update deprecated Python 3.8 typing (#13971)

tests/async_engine/api_server_async_engine.py

@@ -1,6 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 """vllm.entrypoints.api_server with some extra logging for testing."""
-from typing import Any, Dict, Iterable
+from collections.abc import Iterable
+from typing import Any
 
 import uvicorn
 from fastapi.responses import JSONResponse, Response
@@ -24,7 +25,7 @@ class AsyncLLMEngineWithStats(AsyncLLMEngine):
         self._num_aborts += len(ids)
         await super()._engine_abort(ids)
 
-    def testing_stats(self) -> Dict[str, Any]:
+    def testing_stats(self) -> dict[str, Any]:
         return {"num_aborted_requests": self._num_aborts}