Add roles to prometheus kubernetes example

Needed with Prometheus 1.0

documentation/examples/prometheus-kubernetes.yml

@@ -32,6 +32,7 @@ scrape_configs:
   - api_servers:
     - 'https://kubernetes.default.svc'
     in_cluster: true
+    role: apiserver
 
   relabel_configs:
   - source_labels: [__meta_kubernetes_role]
@@ -60,6 +61,7 @@ scrape_configs:
   - api_servers:
     - 'https://kubernetes.default.svc'
     in_cluster: true
+    role: endpoint
 
   relabel_configs:
   - source_labels: [__meta_kubernetes_role, __meta_kubernetes_service_annotation_prometheus_io_scrape]
@@ -106,6 +108,7 @@ scrape_configs:
   - api_servers:
     - 'https://kubernetes.default.svc'
     in_cluster: true
+    role: service
 
   relabel_configs:
   - source_labels: [__meta_kubernetes_role, __meta_kubernetes_service_annotation_prometheus_io_probe]
@@ -139,6 +142,7 @@ scrape_configs:
   - api_servers:
     - 'https://kubernetes.default.svc'
     in_cluster: true
+    role: pod
 
   relabel_configs:
   - source_labels: [__meta_kubernetes_role, __meta_kubernetes_pod_annotation_prometheus_io_scrape]