docs: remove [Unreleased] from changelog

Co-Authored-By: Niels Swimberghe <3382717+Swimburger@users.noreply.github.com>

Author: devin-ai-integration[bot]

CHANGELOG.md

@@ -2,7 +2,7 @@
 
 All notable changes to this project will be documented in this file.
 
-## [Unreleased] (v4)
+## v4
 
 ### Added