[GolemBridge] Add h2 elements from article content

Else some headers are just missing.
Example article with previously missing movie names:
https://www.golem.de/news/science-fiction-die-zehn-besten-filme-aus-den-spannenden-70ern-2312-179557.html

bridges/GolemBridge.php

@@ -132,7 +132,7 @@ private function extractContent($page)
             $img->src = $img->getAttribute('data-src-full');
         }
 
-        foreach ($content->find('p, h1, h3, img[src*="."]') as $element) {
+        foreach ($content->find('p, h1, h2, h3, img[src*="."]') as $element) {
             $item .= $element;
         }