Marketplace tests update

main.py

@@ -1,5 +1,5 @@
 import logging
-from datetime import datetime
+from datetime import datetime, timezone
 
 from fastapi import Depends, FastAPI, HTTPException
 from fastapi.middleware.cors import CORSMiddleware
@@ -56,7 +56,7 @@ def health_check(db: Session = Depends(get_db)):
         db.execute(text("SELECT 1"))
         return {
             "status": "healthy",
-            "timestamp": datetime.utcnow(),
+            "timestamp": datetime.now(timezone.utc),
             "message": f"{settings.project_name} v{settings.version}",
             "docs": {
                 "swagger": "/docs",