Release v4.0.0 (drapergem#872)

* Update the changelog

* Update the readme

* Bump draper version

* Drop support for Ruby 2.3 in CI

Version 3.1.0

Release 3.0.1 (drapergem#824)

* Update changelog and version.

* Add another entry to the changelog.

Release 3.0.0

release 3.0.0.pre1

Version 2.1.0

Version 2.0.0

Version 1.4.0

Version 1.3.1

Version 1.3.0