Add the possibility to create a CHANGELOG file

[AurelioDeRosa]

In addition to publishing the changes for a release in GitHub, it'd be nice if the task could create a CHANGELOG file in Markdown.

[alexcanessa]

Thanks, it is on the list 👍

[ctesene]

It would also be nice if we just wanted the file created. We already have some tooling around creating the release in GitHub, and have a need to generate a changelog for distribution to other teams (such as QA, etc) so they know what changes were included in the release.