update CHANGELOG

Author: ffakenz

CHANGELOG.md

@@ -23,6 +23,11 @@ changes.
 
 - Submit observations to a `hydra-explorer` via optional `--explorer` option.
 
+- Add API command (POST /snapshot) which allows to adopt the given snapshot as the latest confirmed.
+  * add new `SideLodadSnapshot` client input.
+  * add new `SnapshotSideLoaded` state changed event.
+  * add new `SnapshotSideLoaded` server output.
+
 ## [0.20.0] - 2025-02-04
 
 - **BETA** hydra-node now supports incremental commits in beta mode. We would like to test out this feature