kubeadm: Update versions for 1.20

This PR specifies minimum control plane version,
kubelet version and current K8s version for v1.20.

Signed-off-by: Kommireddy Akhilesh <[email protected]>

Author: Akhilesh2412

cmd/kubeadm/app/constants/constants.go

@@ -421,13 +421,13 @@ var (
 	ControlPlaneComponents = []string{KubeAPIServer, KubeControllerManager, KubeScheduler}
 
 	// MinimumControlPlaneVersion specifies the minimum control plane version kubeadm can deploy
-	MinimumControlPlaneVersion = version.MustParseSemantic("v1.18.0")
+	MinimumControlPlaneVersion = version.MustParseSemantic("v1.19.0")
 
 	// MinimumKubeletVersion specifies the minimum version of kubelet which kubeadm supports
-	MinimumKubeletVersion = version.MustParseSemantic("v1.18.0")
+	MinimumKubeletVersion = version.MustParseSemantic("v1.19.0")
 
 	// CurrentKubernetesVersion specifies current Kubernetes version supported by kubeadm
-	CurrentKubernetesVersion = version.MustParseSemantic("v1.19.0")
+	CurrentKubernetesVersion = version.MustParseSemantic("v1.20.0")
 
 	// SupportedEtcdVersion lists officially supported etcd versions with corresponding Kubernetes releases
 	SupportedEtcdVersion = map[uint8]string{
@@ -439,6 +439,7 @@ var (
 		18: "3.4.3-0",
 		19: "3.4.9-1",
 		20: "3.4.13-0",
+		21: "3.4.13-0",
 	}
 
 	// KubeadmCertsClusterRoleName sets the name for the ClusterRole that allows