Send email to candidate when resume is approved

functions.php

function resume_published_send_email($post_id) {
   if( 'resume' != get_post_type( $post_id ) ) {
		return;
	}
   $post = get_post($post_id);
   $author = get_userdata($post->post_author);

   $message = "
      Hi ".$author->display_name.",
      Your resume, ".$post->post_title." has just been approved at ".get_permalink( $post_id ).". Well done!
   ";
   wp_mail($author->user_email, "Your resume is online", $message);
}
add_action('pending_to_publish', 'resume_published_send_email');
add_action('pending_payment_to_publish', 'resume_published_send_email');