fix: replace deprecated on_event with lifespan

backend/apps/litellm/main.py

@@ -1,4 +1,5 @@
 import sys
+from contextlib import asynccontextmanager
 
 from fastapi import FastAPI, Depends, HTTPException
 from fastapi.routing import APIRoute
@@ -46,7 +47,16 @@ import asyncio
 import subprocess
 import yaml
 
-app = FastAPI()
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    log.info("startup_event")
+    # TODO: Check config.yaml file and create one
+    asyncio.create_task(start_litellm_background())
+    yield
+
+
+app = FastAPI(lifespan=lifespan)
 
 origins = ["*"]
 
@@ -141,13 +151,6 @@ async def shutdown_litellm_background():
         background_process = None
 
 
-@app.on_event("startup")
-async def startup_event():
-    log.info("startup_event")
-    # TODO: Check config.yaml file and create one
-    asyncio.create_task(start_litellm_background())
-
-
 app.state.ENABLE_MODEL_FILTER = ENABLE_MODEL_FILTER
 app.state.MODEL_FILTER_LIST = MODEL_FILTER_LIST