Fix values of version field in cfg/cis-1.20 were wrong (#913)

cfg/cis-1.20/controlplane.yaml

 ---
 controls:
-version: "cis-1.6"
+version: "cis-1.20"
 id: 3
 text: "Control Plane Configuration"
 type: "controlplane"

cfg/cis-1.20/etcd.yaml

 ---
 controls:
-version: "cis-1.6"
+version: "cis-1.20"
 id: 2
 text: "Etcd Node Configuration"
 type: "etcd"

cfg/cis-1.20/master.yaml

 ---
 controls:
-version: "cis-1.6"
+version: "cis-1.20"
 id: 1
 text: "Master Node Security Configuration"
 type: "master"

cfg/cis-1.20/node.yaml

 ---
 controls:
-version: "cis-1.6"
+version: "cis-1.20"
 id: 4
 text: "Worker Node Security Configuration"
 type: "node"

cfg/cis-1.20/policies.yaml

 ---
 controls:
-version: "cis-1.6"
+version: "cis-1.20"
 id: 5
 text: "Kubernetes Policies"
 type: "policies"