Enable access to "networkpolicies" of "networking.k8s.io" API group

Since 1.7, k8s netpol is no longer in beta, so NPC can start subscribing
from the non-beta API group.

prog/weave-kube/weave-daemonset-k8s-1.7.yaml

@@ -33,6 +33,14 @@ items:
           - get
           - list
           - watch
+      - apiGroups:
+          - 'networking.k8s.io'
+        resources:
+          - networkpolicies
+        verbs:
+          - get
+          - list
+          - watch
   - apiVersion: rbac.authorization.k8s.io/v1beta1
     kind: ClusterRoleBinding
     metadata: