The distribution of Kubernete that Red Hat supports is OpenShift. Red Hat is not keeing its kubernetes and docker packages from extras updated to their latest upstream releases, it is basically keeping them available for customers who started using then on the early RHEL 7 days.
You cannot use podman to run Kubernetes. Podman is not a CRI-compatible runtime. You could use CRI-O, but to get that for RHEL you need an OpenShift subscription. I am not aware of anyone who builds CRI-O packages for CentOS or Fedora.
If you really wanna play with upstream Kubernetes you'd better download Kubernetes from someone who builds RPMs compatible with CentOS or Fedora, and dowload Docker from similar sources. It may be easier to play with minikube, that doesn't requires that you have Docker at all, and then you could use podman, buildah, and skopeo to build container images to run under minikube.
Anyway you will be loosing a lot by running plain Kubernetes instead of OpenShift. OpenShift is Kubernetes + lots of stuff. But if you want to play with only things that work under Kubernetes, you'll see that the Kubernetes control plane inside OpenShift 4 is maintained current with a short delay relative to upstream Kubernetes.
