The rpmUtils module is provided yum-utils package, which is only
available for Python 2. There is no replacement for the functionality in
DNF.
There is a proposal to add this functionality to rpm itself, but it's
not really moving forward very much:
https://bugzilla.redhat.com/show_bug.cgi?id=1072972
As a short term solution let's copy the needed parts of rpmUtils.arch
module directly to pungi code base.
Fixes: https://pagure.io/pungi/issue/533
Signed-off-by: Qixiang Wan <qwan@redhat.com>