update changelog

Author: tonyd33

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Features
 
+- [jest-core] Stringify Errors properly with --json flag ([#15329](https://github.com/jestjs/jest/pull/15329))
 - `[babel-jest]` Add option `excludeJestPreset` to allow opting out of `babel-preset-jest` ([#15164](https://github.com/jestjs/jest/pull/15164))
 - `[jest-circus, jest-cli, jest-config]` Add `waitNextEventLoopTurnForUnhandledRejectionEvents` flag to minimise performance impact of correct detection of unhandled promise rejections introduced in [#14315](https://github.com/jestjs/jest/pull/14315) ([#14681](https://github.com/jestjs/jest/pull/14681))
 - `[jest-circus]` Add a `waitBeforeRetry` option to `jest.retryTimes` ([#14738](https://github.com/jestjs/jest/pull/14738))