add warning about current state of heketi (#6888)

contrib/network-storage/heketi/README.md

@@ -1,6 +1,11 @@
 # Deploy Heketi/Glusterfs into Kubespray/Kubernetes
 This playbook aims to automate [this](https://github.com/heketi/heketi/blob/master/docs/admin/install-kubernetes.md) tutorial. It deploys heketi/glusterfs into kubernetes and sets up a storageclass.
 
+## Important notice
+> Due to resource limits on the current project maintainers and general lack of contributions we are considering placing Heketi into a near-maintenance mode.[...]
+
+https://github.com/heketi/heketi#important-notice
+
 ## Client Setup
 Heketi provides a CLI that provides users with a means to administer the deployment and configuration of GlusterFS in Kubernetes. [Download and install the heketi-cli](https://github.com/heketi/heketi/releases) on your client machine.