Update readme example for kibana v6.

Closes #14

README.md

@@ -85,7 +85,7 @@ resource "elasticsearch_kibana_object" "test_dashboard" {
   body = "${file("dashboard_path.txt")}"
 }
 
-resource "elasticsearch_kibana_object" "test_visualization" {
+resource "elasticsearch_kibana_object" "test_visualization_v5" {
   body = <<EOF
 [
   {
@@ -105,6 +105,30 @@ resource "elasticsearch_kibana_object" "test_visualization" {
 ]
 EOF
 }
+
+resource "elasticsearch_kibana_object" "test_visualization_v6" {
+  body = <<EOF
+[
+  {
+    "_id": "visualization:response-time-percentile",
+    "_type": "doc",
+    "_source": {
+      "type": "visualization",
+      "visualization": {
+        "title": "Total response time percentiles",
+        "visState": "{\"title\":\"Total response time percentiles\",\"type\":\"line\",\"params\":{\"addTooltip\":true,\"addLegend\":true,\"legendPosition\":\"right\",\"showCircles\":true,\"interpolate\":\"linear\",\"scale\":\"linear\",\"drawLinesBetweenPoints\":true,\"radiusRatio\":9,\"times\":[],\"addTimeMarker\":false,\"defaultYExtents\":false,\"setYExtents\":false},\"aggs\":[{\"id\":\"1\",\"enabled\":true,\"type\":\"percentiles\",\"schema\":\"metric\",\"params\":{\"field\":\"app.total_time\",\"percents\":[50,90,95]}},{\"id\":\"2\",\"enabled\":true,\"type\":\"date_histogram\",\"schema\":\"segment\",\"params\":{\"field\":\"@timestamp\",\"interval\":\"auto\",\"customInterval\":\"2h\",\"min_doc_count\":1,\"extended_bounds\":{}}},{\"id\":\"3\",\"enabled\":true,\"type\":\"terms\",\"schema\":\"group\",\"params\":{\"field\":\"system.syslog.program\",\"size\":5,\"order\":\"desc\",\"orderBy\":\"_term\"}}],\"listeners\":{}}",
+        "uiStateJSON": "{}",
+        "description": "",
+        "version": 1,
+        "kibanaSavedObjectMeta": {
+            "searchSourceJSON": "{\"index\":\"filebeat-*\",\"query\":{\"query_string\":{\"query\":\"*\",\"analyze_wildcard\":true}},\"filter\":[]}"
+        }
+      }
+    }
+  }
+]
+EOF
+}
 ```
 
 ### For use with AWS Elasticsearch domains