docs: Update kubectl version

Update default value of KUBECTL_VERSION to match requirements of
current release.

Issue-ID: DOC-378
Change-Id: I35eb3675fe8e5aba340331512fe378e342a75182
Signed-off-by: Krzysztof Opasiak <k.opasiak@samsung.com>
diff --git a/docs/openstack-rancher.sh b/docs/openstack-rancher.sh
index bcf542a..ac91ff5 100644
--- a/docs/openstack-rancher.sh
+++ b/docs/openstack-rancher.sh
@@ -2,7 +2,7 @@
 
 DOCKER_VERSION=17.03
 RANCHER_VERSION=1.6.22
-KUBECTL_VERSION=1.11.2
+KUBECTL_VERSION=1.11.5
 HELM_VERSION=2.9.1
 
 # setup root access - default login: oom/oom - comment out to restrict access too ssh key only