Use non-deprecated stdout_callback (kubernetes-sigs#10647)

Skippy is deprecated as its functionality has been incorporated into
the default callback plugin.

tests/ansible.cfg

@@ -8,7 +8,8 @@ host_key_checking=False
 gathering = smart
 fact_caching = jsonfile
 fact_caching_connection = /tmp
-stdout_callback = skippy
+stdout_callback = default
+display_skipped_hosts = no
 library = ./library:../library
 callbacks_enabled = profile_tasks
 jinja2_extensions = jinja2.ext.do