Add gnu-tar as dependency for dpkg
dpkg, or atleast dpkg-deb requires a more fully tar then what busybox supplies.
Or rather, it fails because ‘—format=gnu’ is not available to busybox tar.
As such, dpkg should depend on the regular tar package.
(from redmine: issue id 9474, created on 2018-09-26, closed on 2019-06-19)