Add information about multi-arch images to the Readme
Add information about multi-arch images to the Readme

Signed-off-by: Yulia Gaponenko <4e1e642fe1866b37c57d72b7676d11bb58a731a1@de.ibm.com>

nalind/buildah,nalind/buildah-1,nalind/buildah-1,nalind/buildah-1,rhatdan/buildah,rhatdan/buildah,rhatdan/buildah,TomSweeneyRedHat/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,projectatomic/buildah,projectatomic/buildah,TomSweeneyRedHat/buildah,nalind/buildah