fix: dpkg find copyright by bmsuseluda · Pull Request #302 · linuxdeploy/linuxdeploy

Without it linuxdeploy throws about 100 warnings in my build, that copyright files can not be found. You can see it here: https://github.com/bmsuseluda/ares-emu-appimage/actions/runs/13240659936/job/36955122575#step:8:954

And this is because of the absolute path that is used right now. I looked on the system and dpkg can find the copyright files, but not reliably with this absolute path. With just the filename dpkg finds the correct copyright as you can see here: https://github.com/bmsuseluda/ares-emu-appimage/actions/runs/13161636934/job/36731614392#step:8:1

The filesize between these 2 is nearly the same, so i do not see a problem with unrelated files.
Please let me know if i overlook something here.