Fill in release date for 4.2.4

CHANGELOG.txt

@@ -177,7 +177,7 @@ Changelog
  * Maintenance: Refactor admin color palette to semantic, theme-agnostic design tokens (Thibaud Colas)
 
 
-4.2.4 (xx.xx.2023) - IN DEVELOPMENT
+4.2.4 (25.05.2023)
 ~~~~~~~~~~~~~~~~~~
 
  * Fix: Rectify previous fix for TableBlock becoming uneditable after save (Sage Abdullah)

docs/releases/4.2.4.md

@@ -1,6 +1,6 @@
 # Wagtail 4.2.4 release notes
 
-_Unreleased_
+_May 25, 2023_
 
 ```{contents}
 ---