Fix ansible-config with python3 (#34673)

When using the -c option, like "ansible-config -c ~/.ansible.cfg view"
with python 3, it fail with this error message:

  ERROR! Unsupported configuration file extension for b'/home/misc/.ansible.cfg': .cfg

lib/ansible/config/manager.py

@@ -116,7 +116,7 @@ def get_config_type(cfile):
 
     ftype = None
     if cfile is not None:
-        ext = os.path.splitext(cfile)[-1]
+        ext = to_text(os.path.splitext(cfile)[-1])
         if ext in ('.ini', '.cfg'):
             ftype = 'ini'
         elif ext in ('.yaml', '.yml'):