(Stealing from: @rhatdan 's https://github.com/containers/buildah/pull/2038 )
1 We need to update all packages in the podman image to make sure they are
up2date.
2 reinstall shadow-utils. For some reason the fedora base image does not
include the file capabilities assigned to /usr/bin/newuidmap and
/usr/bin/newgidmap. Reinstalling shadow-utils, brings them back.
3 Add a default user build to the system. This will create the
/etc/subuid and /etc/subgid maps get created correctly.
Once we have this we should be able to build a container starting with a non
privileged user
podman run -ti --user build --device=/dev/fuse -v ./Dockerfile:/Dockerfile:z quay.io/podman/stable podman buildd /
Addresses: #4741
Signed-off-by: TomSweeneyRedHat <tsweeney@redhat.com>