Add Matrix account to participant info (#385)

Co-authored-by: Markus Tacker <[email protected]>

_participants/jbarop.md

@@ -5,4 +5,5 @@ pronouns: he/him
 room-type: [quadruple (with TBD)]
 mastodon: https://chaos.social/@jbarop
 linkedin: https://www.linkedin.com/in/jbarop
+matrix: @jbarop:matrix.im
 ---

_participants/markus.md

@@ -7,4 +7,5 @@ image: https://images.contentful.com/bncv3c2gt878/6CWMgqeZdCmkk6KkIUksgQ/5092209
 contact-via: [email protected]
 room-type: big cabin with Aki
 linkedin: https://www.linkedin.com/in/markustacker
+matrix: @coderbyheart:matrix.im
 ---

index.md

@@ -263,6 +263,11 @@ For more information about the safaris, including prices, see the brochure here
       <a href="{{ participant.linkedin }}" rel="noopener noreferrer">
         <i class="fab fa-linkedin"></i></a>
     {% endif %}
+    {% if participant.matrix != null %}
+      <a href="https://matrix.to/#/{{ participant.matrix }}" rel="noopener noreferrer">
+        <img src="{{ site.baseurl }}/logos/matrix.svg" alt="matrix" class="icon" />
+      </a>
+    {% endif %}
     </nav>
     {% if participant.content != null %}<div class="description">{{ participant.content }}</div>{% endif %}
   </li>