Changelog for OCaml 5.3 (#7299)

Author: cknitt

CHANGELOG.md

@@ -31,6 +31,7 @@
 
 - Remove ignore in res_scanner.ml . https://github.com/rescript-lang/rescript/pull/7280
 - Use the new stdlib modules in the analysis tests. https://github.com/rescript-lang/rescript/pull/7295
+- Build with OCaml 5.3.0. https://github.com/rescript-lang/rescript-compiler/pull/7294
 
 # 12.0.0-alpha.8