Fix boefje container image url (#3622)

Co-authored-by: Jan Klopper <[email protected]>

rocky/katalogus/templates/plugin_container_image.html

@@ -5,7 +5,7 @@
 <div>
     <h2>{% translate "Container image" %}</h2>
     <p>
-        {% translate "The container image for this Boefje is:" %} <a href="{{ plugin.oci_image }}">{{ plugin.oci_image }}</a>
+        {% translate "The container image for this Boefje is:" %} <code>{{ plugin.oci_image }}</code>
     </p>
     <div class="fifty-fifty">
         <div>