update copyright year #21

_includes/footer.html

@@ -12,7 +12,7 @@
 
       <p>
 
-        © <a href="https://wwwen.uni.lu/" target="_parent">Université du Luxembourg</a> {{ site.date | escape }}. All rights reserved.
+        © <a href="https://wwwen.uni.lu/" target="_parent">Université du Luxembourg </a>{{ 'now' | date: "%Y" }}. All rights reserved.
 
       {%- include social.html -%}