Fix typo

templates/footer.html

 <div class="footer">
   <div class="columns is-multiline">
     <div class="column is-one-fourth">
-      <p class="title is-5">Teckisd e.V.</p>
+      <p class="title is-5">Teckids e.V.</p>
       <address>
         {{config.extra.footer.address|safe}}
       </address>