fix: stop argparse from interpreting the example date format

zfs_autobackup/CliBase.py

@@ -81,7 +81,7 @@ def get_parser(self):
  group.add_argument('--no-progress', action='store_true',
  help=argparse.SUPPRESS) # needed to workaround a zfs recv -v bug
  group.add_argument('--utc', action='store_true',
- help='Use UTC instead of local time when dealing with timestamps for both formatting and parsing. To snapshot in an ISO 8601 compliant time format you may for example specify --snapshot-format "%Y-%m-%dT%H:%M:%SZ". Changing this parameter after-the-fact (existing snapshots) will cause their timestamps to be interpreted as a different time than before.')
+ help='Use UTC instead of local time when dealing with timestamps for both formatting and parsing. To snapshot in an ISO 8601 compliant time format you may for example specify --snapshot-format "{}-%%Y-%%m-%%dT%%H:%%M:%%SZ". Changing this parameter after-the-fact (existing snapshots) will cause their timestamps to be interpreted as a different time than before.')
  group.add_argument('--version', action='store_true',
  help='Show version.')