Changelog: Add entry for version 2.2.1

Changelog: Add version number to unreleased section

Changelog: Add version number to unreleased section

Co-Authored-By: Jerome Paul <jerome.paul@greensync.com.au>

Changelog: Add entry for 2.0.0

Co-Authored-By: Jerome Paul <jerome.paul@greensync.com.au>

Changelog: Add entry for v1.4.1

Changelog: Add date for 2.0.0.beta1 release

Changelog: Add entry for 1.4.0

Update changelog for 1.3.1

Update changelog to replace unreleased changes heading with 1.3.0

Update gem version to 1.2.0