fix(ansible): use default stdout callback for ansible-core 2.21

Replaces removed community.general.yaml callback so bootstrap-ssh-ca runs cleanly.

ansible/ansible.cfg

@@ -4,5 +4,6 @@ roles_path = ./roles
 host_key_checking = False
 retry_files_enabled = False
 interpreter_python = auto
-stdout_callback = yaml
+stdout_callback = default
+result_format = yaml
 forks = 20