zammad-13.0.0

Zammad is a web based open source helpdesk/customer support system with many features to manage customer communication via several channels like telephone, facebook, twitter, chat and e-mails.

What's Changed

• Update to Zammad 6.4.0 and perform major dependency updates by @mgruner in #300

Full Changelog: zammad-12.5.1...zammad-13.0.0