Adding 'Last updated on: date' to post info in Genesis

functions.php

//* Add last updated date to the post info in entry header (requires HTML5 theme support)
add_filter( 'genesis_post_info', 'sk_post_info_filter' );
function sk_post_info_filter($post_info) {

	if (get_the_modified_time() != get_the_time()) {
		$post_info = $post_info . '<br/>Last updated on: ' . the_modified_date('F j, Y', '', '', false);
	}
	return $post_info;

}