update changelog.md

Author: abbesBenayache

CHANGELOG.md

@@ -6,7 +6,8 @@ All notable changes to this project will be documented in this file.
 
 ### Changed
 
-- Migrated Bellecour subgraph URL to `https://thegraph.iex.ec/...`
+- Migrated the SDK codebase to ES Modules (ESM).
+- Migrated Bellecour subgraph URL to `https://thegraph.iex.ec` (previously `https://v8.subgraph.iex.ec`).
 
 ## [0.0.2-alpha] - 2025-03-11