Add release note to changelog regarding kafka_consumer

CHANGELOG.md

 ## v1.4 [unreleased]
 
 ### Release Notes
+
+- The `kafka_consumer` input has been updated to support Kafka 0.9 and
+  above style consumer offset handling.  The previous version of this plugin
+  supporting Kafka 0.8 and below is available as the `kafka_consumer_legacy`
+  plugin.
+
 ### Features
 
 - [#2487](https://github.com/influxdata/telegraf/pull/2487): Add Kafka 0.9+ consumer support
@@ -11,7 +17,6 @@
 - [#2882](https://github.com/influxdata/telegraf/pull/2882): Add timezone support for logparser timestamps.
 - [#2814](https://github.com/influxdata/telegraf/pull/2814): Add result_type field for http_response input.
 
-
 ### Bugfixes
 
 - [#2819](https://github.com/influxdata/telegraf/pull/2819): [enh] set db_version at 0 if query version fails