Changelog: Fix release date

Author: frankosterfeld

ChangeLog

@@ -1,7 +1,7 @@
 ChangeLog
 =========
 
-version 0.16.0 (release 2026-02-20)
+version 0.16.0 (release 2026-04-29)
 
  - Add support for selecting backend via environment variable (Balló György)
  - Use default DBus timeout for KWallet check (Nicolas Fella)