Update cylc/flow/workflow_files.py

Co-authored-by: Ronnie Dutta <[email protected]>

cylc/flow/workflow_files.py

@@ -25,7 +25,7 @@
 from contextlib import suppress
 from enum import Enum
 import errno
-from queue import deque
+from collections import deque
 import os
 from pathlib import Path
 import re