Update dashboards instructions (grafana#150)

Author: ppcano

README.md

@@ -28,8 +28,12 @@ Check [the documentation](https://k6.io/docs/results-output/real-time/prometheus
 
 ## Dashboards
 
-[<img src="./images/prometheus-dashboard-k6-test-result.png" width="500"/>](./images/prometheus-dashboard-k6-test-result.png)
+<p>&nbsp;</p>
 
-Pre-built Grafana dashboards are available. Check the [dashboard guide](https://k6.io/docs/results-output/real-time/prometheus-remote-write/#time-series-visualization) how to import and use it from the source code or directly from [Grafana.com](https://grafana.com/grafana/dashboards/18030-test-result).
+[<img src="./images/dashboard-k6-prometheus-upper-section.png" width="500"/>](./images/dashboard-k6-prometheus.png)
 
->Note: The dashboards work with the Native Histogram mapping so it is required to enable it.
+This repo contains the [source code](./grafana/dashboards) of two Grafana dashboards designed to visualize test results: [`k6 Prometheus`](https://grafana.com/grafana/dashboards/19665-k6-prometheus/) and [k6 Prometheus (Native Histograms)](https://grafana.com/grafana/dashboards/18030-k6-prometheus-native-histograms/). 
+
+Refer to the [documentation](https://k6.io/docs/results-output/real-time/prometheus-remote-write/#time-series-visualization) to learn more about these dashboards. You can import them to your Grafana instance or with the docker-compose example on this repo. 
+
+🌟 Special thanks to [jwcastillo](https://github.com/jwcastillo) for his contributions and dedication to improving the dashboards. 

grafana/dashboards/README.md

@@ -15,7 +15,7 @@
       }
     ]
   },
-  "description": "Visualize k6 OSS results stored in Prometheus with Native Histogram. K6_PROMETHEUS_RW_TREND_AS_NATIVE_HISTOGRAM option must be true. ",
+  "description": "Visualize k6 OSS results stored in Prometheus with Native Histograms.",
   "editable": true,
   "fiscalYearStartMonth": 0,
   "graphTooltip": 0,

grafana/dashboards/k6-prometheus-native-histogram.json

@@ -827,8 +827,7 @@
             "mode": "absolute",
             "steps": [
               {
-                "color": "green",
-                "value": null
+                "color": "green"
               }
             ]
           },
@@ -1002,8 +1001,7 @@
             "mode": "absolute",
             "steps": [
               {
-                "color": "green",
-                "value": null
+                "color": "green"
               }
             ]
           },
@@ -1182,8 +1180,7 @@
             "mode": "absolute",
             "steps": [
               {
-                "color": "green",
-                "value": null
+                "color": "green"
               }
             ]
           },
@@ -1352,8 +1349,7 @@
             "mode": "absolute",
             "steps": [
               {
-                "color": "green",
-                "value": null
+                "color": "green"
               }
             ]
           }
@@ -1640,8 +1636,7 @@
             "mode": "absolute",
             "steps": [
               {
-                "color": "green",
-                "value": null
+                "color": "green"
               }
             ]
           }
@@ -1844,8 +1839,7 @@
             "mode": "absolute",
             "steps": [
               {
-                "color": "green",
-                "value": null
+                "color": "green"
               }
             ]
           },
@@ -1977,9 +1971,10 @@
       },
       {
         "current": {
+          "isNone": true,
           "selected": false,
-          "text": "p99",
-          "value": "p99"
+          "text": "None",
+          "value": ""
         },
         "datasource": {
           "type": "prometheus",