add changelog

Author: cometkim

CHANGELOG.md

@@ -33,6 +33,7 @@
 #### :house: Internal
 
 - Clean up legacy tags handling. https://github.com/rescript-lang/rescript/pull/7309
+- Use Yarn (Berry) workspaces for internal tooling. https://github.com/rescript-lang/rescript/pull/7309
 
 #### :nail_care: Polish