Use a backward-compatible way of aware timestamp

Author: avandras

patroni/multisite.py

@@ -4,7 +4,7 @@
 import time
 
 from collections.abc import Callable
-from datetime import datetime
+from datetime import datetime, timezone
 from threading import Event, Thread
 from typing import Any, Dict, List, Optional, TYPE_CHECKING
 
@@ -410,7 +410,7 @@ def __init__(self, crd_name: str, crd_uid: str, reporter: str, crd_api: str):
     def state_transition(self, new_state: str, note: str):
         self._status_update = {"status": {"Multisite": new_state}}
 
-        failover_time = datetime.utcnow().strftime("%Y-%m-%dT%H:%M:%S.%fZ")
+        failover_time = datetime.now(timezone.utc).strftime("%Y-%m-%dT%H:%M:%S.%fZ")
         reason = 'Promote' if new_state == 'Leader' else 'Demote'
 
         # TODO: check if this is needed, no current call comes without note (this is already reflected in the signature)