add Dnsmasq exporter into exporters list (#1338)

Signed-off-by: Matt Pursley <mpursley@gmail.com>

content/docs/instrumenting/exporters.md

@@ -164,6 +164,7 @@ wide variety of JVM-based applications, for example [Kafka](http://kafka.apache.
    * [Cachet exporter](https://github.com/ContaAzul/cachet_exporter)
    * [ccache exporter](https://github.com/virtualtam/ccache_exporter)
    * [Dovecot exporter](https://github.com/kumina/dovecot_exporter)
+   * [Dnsmasq exporter](https://github.com/google/dnsmasq_exporter)
    * [eBPF exporter](https://github.com/cloudflare/ebpf_exporter)
    * [Ethereum Client exporter](https://github.com/31z4/ethereum-prometheus-exporter)
    * [Hostapd Exporter](https://stash.i2cat.net/scm/~miguel_catalan/hostapd_prometheus_exporter.git)