docs: Add changelog entry

Author: DannyvdSluijs

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Added
 - Add lint check for class autoloading PSR compliance ([#845](https://github.com/jsonrainbow/json-schema/pull/845))
+- add implementation for strict fully validating using draft-06 schema ([#843](https://github.com/jsonrainbow/json-schema/pull/835))
 
 ## [6.5.2] - 2025-09-09
 ### Fixed