Fill in release date for 5.0.3

CHANGELOG.txt

@@ -140,7 +140,7 @@ Changelog
  * Maintenance: Don't update the reference index while deleting it (Andy Chosak)
 
 
-5.0.3 (xx.xx.20xx) - IN DEVELOPMENT
+5.0.3 (25.09.2023)
 ~~~~~~~~~~~~~~~~~~
 
  * Fix: Avoid use of `ignore_conflicts` when creating extra permissions for snippets, for SQL Server compatibility (Sage Abdullah)

docs/releases/5.0.3.md

@@ -1,6 +1,6 @@
-# Wagtail 5.0.3 release notes - IN DEVELOPMENT
+# Wagtail 5.0.3 release notes
 
-_Unreleased_
+_September 25, 2023_
 
 ```{contents}
 ---