Fix documentations not being displayed due to timezone mismatch

aleksis/apps/alsijil/models.py

-from datetime import date, datetime
+from datetime import date, datetime, timezone
 from typing import Optional, Union
 from urllib.parse import urlparse
 import json
@@ -553,7 +553,7 @@ class Documentation(CalendarEvent):
                     existing_documentations := (
                         event_reference_obj := event["REFERENCE_OBJECT"]
                     ).documentation.filter(
-                        datetime_start=event["DTSTART"].dt, datetime_end=event["DTEND"].dt
+                        datetime_start=event["DTSTART"].dt.replace(tzinfo=timezone.utc), datetime_end=event["DTEND"].dt.replace(tzinfo=timezone.utc)
                     )
                 ).exists()
                 else cls(