chore: ammending chanelog

CHANGELOG.md

@@ -22,14 +22,21 @@ should change the heading of the (upcoming) version to include a major version b
 - add `retrieveSchema` at `Form` state to memoize the result of `schemUtils.retrieveSchema`
 
 ## @rjsf/fluentui-rc
+
 - Updated README.md references
 - Fixed width of `ArrayFieldItemTemplate` items
 
-## Dev
+## @rjsf/utils
+
+- Added an experimental flag `allOf` to `experimental_defaultFormStateBehavior` for populating defaults when using `allOf` schemas [#3969](https://github.com/rjsf-team/react-jsonschema-form/pull/3969)
+
+## Dev / playground
+
 - update tsconfigs:
   - `"importHelpers": false` to remove need for tslib dependency [#3958](https://github.com/rjsf-team/react-jsonschema-form/issues/3958)
   - increase compilation target level from es6 to es2018 (so there are no need for transpiling object spread/rest feature)
   - add missing typescript project reference for `snapshot-tests` in a root tsconfig, update it to also use es modules
+- Added a dropdown for chaning the `experimental_defaultFormStateBehavior.allOf` behaviour in the playground
 
 # 5.14.2