add CHANGELOG

Author: cometkim

CHANGELOG.md

@@ -17,6 +17,7 @@
 - `lazy` syntax is no longer supported. If you're using it, use `Lazy` module or `React.lazy_` instead. https://github.com/rescript-lang/rescript-compiler/pull/6342
 - Remove handling of attributes with `bs.` prefix (`@bs.as` -> `@as` etc.). https://github.com/rescript-lang/rescript-compiler/pull/6643
 - Remove obsolete `@bs.open` feature. https://github.com/rescript-lang/rescript-compiler/pull/6629
+- Drop Node.js version <18 support, due to it reaching End-of-Life. https://github.com/rescript-lang/rescript-compiler/pull/6429
 
 #### :house: Internal