message: Add Changelog for 21.1.0
diff: -## master
  +## jest 21.1
  +
  +* (minor) Use ES module exports ([#4454](https://github.com/facebook/jest/pull/4454))
  +* Allow chaining mockClear and mockReset ([#4475](https://github.com/facebook/jest/pull/4475))
  +* Call jest-diff and pretty-format more precisely in toHaveProperty matcher ([#4445](https://github.com/facebook/jest/pull/4445))
  +* Expose restoreAllMocks to object ([#4463](https://github.com/facebook/jest/pull/4463))
  +* Fix function name cleaning when making mock fn ([#4464](https://github.com/facebook/jest/pull/4464))
  +* Fix Map/Set equality checker ([#4404](https://github.com/facebook/jest/pull/4404))
  +* Make FUNCTION_NAME_RESERVED_PATTERN stateless ([#4466](https://github.com/facebook/jest/pull/4466))
  +
  +## jest 21.0.2
  * Take precedence of NODE_PATH when resolving node_modules directories ([#4453](https://github.com/facebook/jest/pull/4453))
  * Fix race condition with --coverage and babel-jest identical file contents edge case ([#4432](https://github.com/facebook/jest/pull/4432))
  * Add extra parameter `--runTestsByPath`. ([#4411](https://github.com/facebook/jest/pull/4411))
  * Upgrade all outdated deps ([#4425](https://github.com/facebook/jest/pull/4425))
  -# jst 21.0.1
  +# jest 21.0.1
  * Remove obsolete error ([#4417](https://github.com/facebook/jest/pull/4417))
  