log4j/log4shell vulnerability: UCS and third-party app updates

UCS 5.0-0 does ship apache-log4j2 as a Debian package, but this is not in use by default. We have already made updates for this package available to our customers on 12/13/2021, as they are not included in the regular errata tracking. For more information on the update, please visit the help forum at: https://help.univention.com/t/status-of-log4j-log4shell-vulnerability-cve-2021-44228-in-ucs-and-apps/19020.