Update tarLongFileMode to use POSIX

Expected behavior

No response

Actual behavior

No response

Steps to reproduce the problem

Mapstruct fails to build when the UID and/or GID of the user who executed the build is bigger than 2097151. This is happening when building this project in an OpenShift environment.

A fix for this is to use the TarArchiver behavior POSIX instead of GNU.

MapStruct Version

1.5.5.Final