fix: handle UTC import for Python versions below 3.11

src/submission/submit.py

@@ -1,6 +1,7 @@
 import json
 import os
-from datetime import UTC, datetime, timezone
+import sys
+from datetime import datetime, timezone
 
 from src.display.formatting import styled_error, styled_message, styled_warning
 from src.envs import API, EVAL_REQUESTS_PATH, QUEUE_REPO, TOKEN
@@ -11,6 +12,11 @@ from src.submission.check_validity import (
     is_model_on_hub,
 )
 
+if sys.version_info < (3, 11):
+    UTC = timezone.utc
+else:
+    from datetime import UTC
+
 REQUESTED_MODELS = None
 USERS_TO_SUBMISSION_DATES = None