Update CHANGELOG.

Author: neunhoef

CHANGELOG.md

@@ -3,6 +3,8 @@
 ## [0.3.13]() (XXXX-XX-XX)
 - Added side car changed to pod rotation criterium
 - Added ArangoDB version and image id to member status
+- Fix bug with MemberOfCluster condition
+- Added test for resource change
 
 ## [0.3.12](https://github.com/arangodb/kube-arangodb/tree/0.3.12) (2019-07-04)
 - Limit source IP ranges for external services