CLOUD-65865 added changelog for 1.6
CLOUD-65865 added changelog for 1.6

hortonworks/cloudbreak,sequenceiq/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,hortonworks/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak,hortonworks/cloudbreak,sequenceiq/cloudbreak