message: docs: update CHANGELOG 0.4.0 release date
diff: @@ -11,7 +11,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  - [#114](https://github.com/ClementTsang/bottom/pull/114): Process state per process (originally in 0.4.0, moved to later).
  -## [0.4.0] - Unreleased
  +## [0.4.0] - 2020-05-04
  ### Features
  