Merge pull request #4843 from afbjorklund/k8s-flannel-0.28.2

Bump k8s flannel version from 0.27.4 to 0.28.4

Author: AkihiroSuda

templates/k8s.yaml

@@ -136,7 +136,7 @@ provision:
 
     {{if not ( and .Param.url .Param.token )}}
     # Installing a Pod network add-on
-    kubectl apply -f https://github.com/flannel-io/flannel/releases/download/v0.27.4/kube-flannel.yml
+    kubectl apply -f https://github.com/flannel-io/flannel/releases/download/v0.28.4/kube-flannel.yml
     # Control plane node isolation
     kubectl taint nodes --all node-role.kubernetes.io/control-plane-
     # Symlink the kubeconfig file to the default location for kubectl