CHANGELOG outdated (no mention of version 3 and ulterior)

The last release covered in [CHANGELOG.md](https://github.com/flauc/angular2-notifications/blob/master/CHANGELOG.md) is 2.0.0. This is missing at least versions 3 and... 9, it seems.

As reported in ticket #341 this is not the first time the changelog is outdated. It would be great if the release process could ensure a minimal update.