docs: update CHANGELOG

Author: jpraynaud

CHANGELOG.md

@@ -13,6 +13,8 @@ As a minor extension, we have adopted a slightly different versioning convention
 
   - Upgraded the minimum required `glibc` version from `2.31` to `2.35` for the pre-built Linux binaries.
 
+- Support for `Cardano node` `10.2.1` in the signer and the aggregator.
+
 - End support for **macOS x64 pre-built binaries** for the client CLI.
 
 - **UNSTABLE** Implement a slave signer registration mode in the aggregator.