Allow format of publish_date

It would be great if you can format the publish date. e.g.

In the field.php, line 248, perhaps change the code to add the check and set the value:

case ‘publish_date’:
if (isset( $args[‘format’] )) {
$value = date($args[‘format’], strtotime( $post->post_date ));
}
else {
$value = $post->post_date;
}
return $value;
break;