Update CHANGELOG

Author: emasab

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Confluent's Python client for Apache Kafka
 
+## v2.3.1 (can change before next release)
+
+ - Remove LICENCE.txt that was incorrectly installed as a data file (@dirkmueller, @asottile-sentry)
+
+confluent-kafka-python is based on librdkafka v2.3.1, see the
+[librdkafka release notes](https://github.com/confluentinc/librdkafka/releases/tag/v2.3.1)
+for a complete list of changes, enhancements, fixes and upgrade considerations.
+
 ## v2.3.0
 
 v2.3.0 is a feature release with the following features, fixes and enhancements: