ansible.cfg: do not enforce PreferredAuthentications

There's no need to enforce PreferredAuthentications by default.
Users can still choose to override the ansible.cfg with any additional
parameter like this one to fit their infrastructure.

Fixes: #4826
Signed-off-by: Guillaume Abrioux <gabrioux@redhat.com>
(cherry picked from commit d682412e)

ansible.cfg

@@ -30,7 +30,7 @@ timeout = 60
 [ssh_connection]
 # see: https://github.com/ansible/ansible/issues/11536
 control_path = %(directory)s/%%h-%%r-%%p
-ssh_args = -o ControlMaster=auto -o ControlPersist=600s -o PreferredAuthentications=publickey
+ssh_args = -o ControlMaster=auto -o ControlPersist=600s
 pipelining = True
 
 # Option to retry failed ssh executions if the failure is encountered in ssh itself