MFH: r541824

MyBB 1.8.22 is now available, and is a security & maintenance release.

Changelog: https://blog.mybb.com/2019/12/30/mybb-1-8-22-released-security-maintenance-release/

Security: 198a120d-c22d-11ea-9172-4c72b94353b5
Sponsored by: Netzkommune GmbH

Approved by: ports-secteam (with hat)