Add CHANGELOG-5.0 entry for computeHmac ValueError fix

Agent-Logs-Url: https://github.com/phalcon/cphalcon/sessions/c782ce96-4b3b-4de0-bfb7-a9cbddfd9d31

Co-authored-by: niden <1073784+niden@users.noreply.github.com>

Author: Copilot

CHANGELOG-5.0.md

@@ -9,6 +9,8 @@
 
 ### Fixed
 
+- Fixed `Phalcon\Encryption\Security::computeHmac()` to catch `\ValueError` thrown by PHP 8.1+ when an unknown hashing algorithm is passed [#16893](https://github.com/phalcon/cphalcon/issues/16893)
+
 ### Removed
 
 ## 5.11.0 (2026-04-03)