[concrete5] Add express entry details into sitemap.xml

app.php

<?php
/* @var Concrete\Core\Application\Application $app */
/* @var Concrete\Core\Console\Application $console only set in CLI environment */

/** @var \Symfony\Component\EventDispatcher\EventDispatcherInterface $director */
$director = $app->make(\Symfony\Component\EventDispatcher\EventDispatcherInterface::class);
$director->addListener('on_sitemap_xml_ready', static function ($event) use ($app) {
    /** @var \Concrete\Core\Page\Sitemap\Event\XmlReadyEvent $event */
    $xml = $event->getDocument();

    $entity = Express::getObjectByHandle('test');
    if (is_object($entity)) {
        $resolver = $app->make(\Concrete\Core\Url\Resolver\Manager\ResolverManagerInterface::class);
        $list = new \Concrete\Core\Express\EntryList($entity);
        $entries = $list->getResults();
        /** @var \Concrete\Core\Entity\Express\Entry $entry */
        foreach ($entries as $entry) {
            $id = $entry->getID();
            $lastMod = $entry->getDateModified()->format(DateTime::ATOM);
            $url = $xml->addChild('url');
            $url->addChild('loc', $resolver->resolve(['/express/detail/', 'view_express_entity', $id]));
            $url->addChild('lastmod', $lastMod);
            $url->addChild('priority', 0.5);
            $url->addChild('changefreq', 'weekly');
        }
    }

    $event->setDocument($xml);
});