linux: ensure Debian package files are owned by root

Ensure that the files included in the Debian package are owned by the
root user and not which ever user on the local system built the package.

Author: mjcheetham

src/linux/Packaging.Linux/pack.sh

@@ -126,6 +126,6 @@ if [ ! -f "$LINK_TO/git-credential-manager" ]; then
         "$LINK_TO/git-credential-manager" || exit 1
 fi
 
-dpkg-deb -Zxz --build "$DEBROOT" "$DEBPKG" || exit 1
+dpkg-deb -Zxz --root-owner-group --build "$DEBROOT" "$DEBPKG" || exit 1
 
 echo $MESSAGE