Convert PolicyConfig licence header to SPDX

I don't have the contact email of the original author and it is not easy to trace back to the source because the project has been split and forked
1 job for master in 5 minutes and 39 seconds (queued for 52 minutes and 14 seconds)
Status Job ID Name Coverage
  Build
passed #92814
linux kf5-qt5 qt5.15

00:05:39

16.0%