actualized for kubespray version 2.28.0

kubespray/project/roles/network_plugin/flannel/defaults/main.yml

@@ -2,7 +2,7 @@
 # Flannel public IP
 # The address that flannel should advertise as how to access the system
 # Disabled until https://github.com/coreos/flannel/issues/712 is fixed
-# flannel_public_ip: "{{ access_ip | default(ip | default(fallback_ips[inventory_hostname])) }}"
+# flannel_public_ip: "{{ main_access_ip }}"
 
 ## interface that should be used for flannel operations
 ## This is actually an inventory cluster-level item