Prepare release 5.4.1

Author: jensens

CHANGES.md

@@ -1,9 +1,12 @@
 ## Changes
 
-## 5.4.1 (unreleased)
+## 5.4.2 (unreleased)
 
 <!-- Add future changes here -->
 
+
+## 5.4.1 (2026-08-04)
+
 - Fix #100: With packaging >= 26.3, packages configured as sources were no longer
   commented out in the generated requirements/constraints, because `Requirement()`
   now rejects the trailing newline and the error was silently swallowed. Lines are