docs: add changelog entry for seroval upgrade

Author: jsourcebot

CHANGELOG.md

@@ -7,6 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- Upgraded `seroval` to `^1.5.6`. [#1508](https://github.com/sourcebot-dev/sourcebot/pull/1508)
+
 ### Changed
 - Vulnerability triage now keeps Linear issues synchronized with current security findings.