Release k8s v1.11.8, v1.12.6 and v1.13.4
Release k8s v1.11.8, v1.12.6 and v1.13.4

Release new k8s version because of CVE-2019-1002100[1]

[1] https://discuss.kubernetes.io/t/kubernetes-security-announcement-v1-11-8-1-12-6-1-13-4-released-to-address-medium-severity-cve-2019-1002100/5147

Task: 29789
Story: 2005124

Change-Id: I6435a10b05932ea71e825e944d53859eba374e91

ArchiFleKs/magnum,openstack/magnum,openstack/magnum,ArchiFleKs/magnum