Disable kubernetes dashboard installation

Kubespray uses a stable version of the K8s dashboard which does
not support later versions of Kubernetes [1] (e.g. v1.16.0).
Right now, there are only RCs available, so the bug will be present
until a new stable build is published.

[1] https://github.com/kubernetes-sigs/kubespray/issues/5347

Change-Id: I22ce421de04d499b4961503550a51e17c36f5478
1 file changed