Pinning the mattermost version

At the moment whatever mattermost version is current when the service is installed will be kept and not upgraded. It’s not ideal and it would be better to:

  • Pin a version in the playbook
  • Upgrade to the version pinned when running the playbook is currently 5.1.0 and that’s what should be pinned first before upgrading to 5.23+

But 5.1.0 no longer builds because of was upgraded to 5.23

The upgrade also sent a survey mail to all users which is quite bad :frowning: