fix utc time zone (#592)

Author: Lucas Gameiro

src/backups.py

@@ -8,7 +8,7 @@
 import os
 import re
 import tempfile
-from datetime import datetime
+from datetime import datetime, timezone
 from typing import Dict, List, Optional, OrderedDict, Tuple
 
 import boto3 as boto3
@@ -362,7 +362,9 @@ def _generate_backup_list_output(self) -> str:
                 backup_reference, _ = self._parse_backup_id(backup["reference"][-1])
             lsn_start_stop = f'{backup["lsn"]["start"]} / {backup["lsn"]["stop"]}'
             time_start, time_stop = (
-                datetime.strftime(datetime.fromtimestamp(stamp), "%Y-%m-%dT%H:%M:%SZ")
+                datetime.strftime(
+                    datetime.fromtimestamp(stamp, timezone.utc), "%Y-%m-%dT%H:%M:%SZ"
+                )
                 for stamp in backup["timestamp"].values()
             )
             backup_path = f'/{self.stanza_name}/{backup["label"]}'