metrics: use HTTPS URLs

README.md

@@ -542,14 +542,14 @@ _See also: [Databases](#databases)_
   - [Telegraf](https://github.com/influxdata/telegraf) - The plugin-driven server agent for collecting & reporting metrics.
 
 * Dashboards
-  - [Facette](http://facette.io) - Time series data visualization and graphing software written in Go.
-  - [Grafana](http://grafana.org/) - A Graphite & InfluxDB Dashboard and Graph Editor.
-  - [RRDtool](http://oss.oetiker.ch/rrdtool/) - Industry standard, high performance data logging and graphing system for time series data.
+  - [Facette](https://facette.io) - Time series data visualization and graphing software written in Go.
+  - [Grafana](https://grafana.com/) - A Graphite & InfluxDB Dashboard and Graph Editor.
+  - [RRDtool](https://oss.oetiker.ch/rrdtool/) - Industry standard, high performance data logging and graphing system for time series data.
 
 * Packages
   - [Beats](https://www.elastic.co/beats/) - Single-purpose data shippers that send data from hundreds or thousands of machines and systems to Logstash or Elasticsearch.
-  - [Graphite](http://graphite.readthedocs.org/en/latest/) - Scalable graphing server.
-  - [Prometheus](http://prometheus.io/) - Service monitoring system and time series database.
+  - [Graphite](https://graphite.readthedocs.org/en/latest/) - Scalable graphing server.
+  - [Prometheus](https://prometheus.io/) - Service monitoring system and time series database.
   - [VictoriaMetrics](https://github.com/VictoriaMetrics/VictoriaMetrics) - Service monitoring system and time series database.