feat: improve header of article

templates/post.html

@@ -4,7 +4,10 @@
 <article>
     <section class=title>
         <h1 class=title>{{ page.title }}</h1>
-        <p class=subtitle>{{ page.date }}</p>
+        {% if page.description %}
+        <p class=subtitle>{{ page.description }}</p>
+        {% endif %}
+        <p class=metadata>par {{ page.authors | join(sep=', ') }} le {{ page.date }}{% if page.updated %} (mise à jour : {{ page.updated }}){% endif %}</p>
     </section>
     <section>
         {{ page.content | safe }}