Rename master to control plane - non-breaking changes only (#11394)

K8s is moving away from the "master" terminology, so kubespray should follow the same naming conventions. See 65d886bb30/sig-architecture/naming/recommendations/001-master-control-plane.md

roles/kubernetes/control-plane/tasks/kubeadm-upgrade.yml

@@ -9,7 +9,7 @@
   delay: 5
   until: _result.status == 200
 
-- name: Kubeadm | Upgrade first master
+- name: Kubeadm | Upgrade first control plane node
   command: >-
     timeout -k 600s 600s
     {{ bin_dir }}/kubeadm
@@ -28,9 +28,9 @@
   failed_when: kubeadm_upgrade.rc != 0 and "field is immutable" not in kubeadm_upgrade.stderr
   environment:
     PATH: "{{ bin_dir }}:{{ ansible_env.PATH }}"
-  notify: Master | restart kubelet
+  notify: Control plane | restart kubelet
 
-- name: Kubeadm | Upgrade other masters
+- name: Kubeadm | Upgrade other control plane nodes
   command: >-
     timeout -k 600s 600s
     {{ bin_dir }}/kubeadm
@@ -49,7 +49,7 @@
   failed_when: kubeadm_upgrade.rc != 0 and "field is immutable" not in kubeadm_upgrade.stderr
   environment:
     PATH: "{{ bin_dir }}:{{ ansible_env.PATH }}"
-  notify: Master | restart kubelet
+  notify: Control plane | restart kubelet
 
 - name: Kubeadm | Remove binding to anonymous user
   command: "{{ kubectl }} -n kube-public delete rolebinding kubeadm:bootstrap-signer-clusterinfo --ignore-not-found"