add opengraph metadata for attached podcast

panikweb_templates/templates/emissions/episode_detail.html

@@ -12,6 +12,10 @@
 {% if episode.subtitle %}
 <meta property="og:description" content="{{ episode.subtitle }}" />
 {% endif %}
+{% if episode.main_sound %}
+<meta property="og:audio" content="{{ episode.main_sound|format_url:'ogg' }}"/>
+<meta property="og:audio:type" content="audio/ogg"/>
+{% endif %}
 {% endblock %}
 
 {% block related %}