Update CHANGELOG.md

Author: GrahamCampbell

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [10.4.0]: https://github.com/GitLabPHP/Client/compare/10.3.1...10.4.0
 
 * Add min_access_level option to group search
+* Added support for additional issue order clauses
 * Added params array to remove user method to support hard_delete
 
 ## [10.3.1] - 2020-12-04