Update CHANGELOG

Author: ajanikow

CHANGELOG.md

@@ -1,6 +1,8 @@
 # Change Log
 
 ## [master](https://github.com/arangodb/kube-arangodb/tree/master) (N/A)
+
+## [1.1.8](https://github.com/arangodb/kube-arangodb/tree/1.1.8) (2021-04-21)
 - Prevent Single member recreation
 - Add OwnerReference to ClusterIP member service
 - Add InternalPort to ServerGroupSpec to allow user to expose tcp connection over localhost for sidecars