Add connbeat to the list (elastic#3437)

libbeat/docs/communitybeats.asciidoc

@@ -14,6 +14,7 @@ https://github.com/goomzee/burrowbeat[burrowbeat]:: Monitors Kafka consumer lag
 https://github.com/goomzee/cassandrabeat[cassandrabeat]:: Uses Cassandra's nodetool cfstats utility to monitor Cassandra database nodes and lag.
 https://github.com/hartfordfive/cloudflarebeat[cloudflarebeat]:: Indexes log entries from the Cloudflare Enterprise Log Share API.
 https://github.com/aidan-/cloudtrailbeat[cloudtrailbeat]:: Reads events from Amazon Web Services' https://aws.amazon.com/cloudtrail/[CloudTrail].
+https://github.com/raboof/connbeat[connbeat]:: Exposes metadata about TCP connections
 https://github.com/Pravoru/consulbeat[consulbeat]:: Reads services health checks from consul and pushes them to elastic.
 https://github.com/Ingensi/dockbeat[dockbeat]:: Reads Docker container
 statistics and indexes them in Elasticsearch.