Prepare release 1.4.0

Workflow: Release stage 1 - create release PR, run: 18

Author: github-actions[bot]

CHANGES.md

@@ -11,7 +11,7 @@ creating a new release entry be sure to copy & paste the span tag with the
 updated. Only the first match gets replaced, so it's fine to leave the old
 ones in. -->
 
-## __cylc-ui-1.4.0 (<span actions:bind='release-date'>Pending</span>)__
+## __cylc-ui-1.4.0 (<span actions:bind='release-date'>Released 2023-01-16</span>)__
 
 ### Enhancements