Do not use ‘yes/no’ for boolean values (#11472)

Consistent boolean values in ansible playbooks

roles/etcd/tasks/main.yml

@@ -33,7 +33,7 @@
   command: "openssl x509 -in {{ etcd_cert_dir }}/node-{{ inventory_hostname }}.pem -noout -serial"
   register: "etcd_client_cert_serial_result"
   changed_when: false
-  check_mode: no
+  check_mode: false
   when:
     - kube_network_plugin in ["calico", "flannel", "cilium"] or cilium_deploy_additionally | default(false) | bool
     - kube_network_plugin != "calico" or calico_datastore == "etcd"