Bug fix: missing closing tag

There were a missing closing tag that had an impact on the footer
display.
Signed-off-by: Matthieu Berjon <matthieu.berjon@inria.fr>

django/allgo/static/css/allgo.css

@@ -273,6 +273,7 @@ a {
 }
 .webapp-tags-update {
   width: 100%;
+}
 
 /* font-awesome disabled buttons
  *