Change /ping to post endpoint per AWS documentation

Signed-off-by: Nathan Azrak <[email protected]>

vllm/entrypoints/openai/api_server.py

@@ -319,7 +319,7 @@ async def health(raw_request: Request) -> Response:
     return Response(status_code=200)
 
 
-@router.get("/ping")
+@router.post("/ping")
 async def ping(raw_request: Request) -> Response:
     """Ping check. Endpoint required for SageMaker"""
     return await health(raw_request)