Add kube-state-metrics to miscellaneous exporters (#1266)

Signed-off-by: Frederic Branczyk <fbranczyk@gmail.com>

content/docs/instrumenting/exporters.md

@@ -162,6 +162,7 @@ wide variety of JVM-based applications, for example [Kafka](http://kafka.apache.
    * [Kannel exporter](https://github.com/apostvav/kannel_exporter)
    * [Kemp LoadBalancer exporter](https://github.com/giantswarm/prometheus-kemp-exporter)
    * [Kibana Exporter](https://github.com/pjhampton/kibana-prometheus-exporter)
+   * [kube-state-metrics](https://github.com/kubernetes/kube-state-metrics)
    * [Meteor JS web framework exporter](https://atmospherejs.com/sevki/prometheus-exporter)
    * [Minecraft exporter module](https://github.com/Baughn/PrometheusIntegration)
    * [OpenStack exporter](https://github.com/Linaro/openstack-exporter)