memo: Update link in release notes
## Next release
-* Update docs for testing FastAPI. Include using `POST`, sending JSON, testing headers, etc. New documentation: [Testing](https://fastapi.tiangolo.com/tutorial/testing/). PR [#271](https://github.com/tiangolo/fastapi/pull/271).
+* Update docs for testing FastAPI. Include using `POST`, sending JSON, testing headers, etc. New documentation: [Testing](https://fastapi.tiangolo.com/tutorial/testing/#testing-extended-example). PR [#271](https://github.com/tiangolo/fastapi/pull/271).
* Fix type declaration of `response_model` to allow generic Python types as `List[Model]`. Mainly to fix `mypy` for users. PR [#266](https://github.com/tiangolo/fastapi/pull/266).
