Update contrib/kube-prometheus

jsonnetfile.lock.json

@@ -8,7 +8,7 @@
                     "subdir": "contrib/kube-prometheus/jsonnet/kube-prometheus"
                 }
             },
-            "version": "dff8f44fbce268596c86b8d586c64c17953feab3"
+            "version": "9cc151ced4308573a91f4cc3fcdbc951213b03e0"
         },
         {
             "name": "ksonnet",

manifests/prometheus-rules.yaml

@@ -790,7 +790,7 @@ spec:
         message: Alertmanager has not found all other members of the cluster.
       expr: |
         alertmanager_cluster_members{job="alertmanager-main"}
-          != on (service)
+          != on (service) GROUP_LEFT()
         count by (service) (alertmanager_cluster_members{job="alertmanager-main"})
       for: 5m
       labels: