Convert wp_page_menu() to wp_nav_menu() markup

functions.php

<?php

$html = wp_page_menu( array(
	'echo' => false,
	'depth' => 2
) );

$html = str_replace( ' page_item_has_children', ' menu-item-has-children', $html );
$html = str_replace( ' current_page_item',      ' current-menu-item',      $html );
$html = str_replace( ' page-item-',             ' menu-item-',             $html );
$html = str_replace( 'class="page_item',        'class="menu-item',        $html );
$html = str_replace( "class='children'",        'class="sub-menu"',        $html );

return $html;