http-client-0.4.1: ChangeLog.md

## 0.4.1

* Provide the `responseOpenHistory`/`withResponseHistory` API. See: https://github.com/snoyberg/http-client/pull/79

## 0.4.0

* Hide the `Part` constructor, and allow for additional headers. See: https://github.com/snoyberg/http-client/issues/76