docs: update CHANGELOG

Author: Clément Turmel

CHANGELOG.md

@@ -19,6 +19,8 @@ As a minor extension, we have adopted a slightly different versioning convention
 
 - Support for stable `v2` backend of `cardano-db` command and decommission of the `cardano-db-v2` command in client CLI.
 
+- Support for stable Cardano database v2 backend in aggregator.
+
 - Add a new `/certificate/genesis` route to the aggregator that fetches the latest genesis certificate
 
 - Abstracted the implementation of KES signature and verification to allow multiple and reusable implementations.