restic diff: fix regex filter

plugins/transfer/restic.sh

@@ -207,7 +207,7 @@
         local _snapshotNow
 
         # get list of snapshots and filter the lines with a date YYYY-MM-DD
-        _data=$( t_restoreDoShowVolumes | grep "[12][0-9][0-9][0-1]-[0-2][0-9]-[0-3][0-9]" | tail -5 )
+        _data=$( t_restoreDoShowVolumes | grep "[12][0-9][0-9][0-9]-[0-2][0-9]-[0-3][0-9]" | tail -5 )
         echo "..."
         echo "$_data"