Bump copyright year, old style

COPYING

-Copyright 2007-2020 UNINETT AS, https://www.uninett.no
+Copyright 2007-2021 UNINETT AS, https://www.uninett.no
 
 SimpleSAMLphp is licensed under the CC-GNU LGPL version 2.1.
 http://creativecommons.org/licenses/LGPL/2.1/

templates/includes/footer.php

@@ -9,7 +9,7 @@ if (!empty($this->data['htmlinject']['htmlContentPost'])) {
             <div id="footer">
                 <hr />
                 <img src="/<?php echo $this->data['baseurlpath']; ?>resources/icons/ssplogo-fish-small.png" alt="Small fish logo" style="float: right" />		
-                    Copyright &copy; 2007-2020 <a href="https://uninett.no/">UNINETT AS</a>
+                    Copyright &copy; 2007-2021 <a href="https://uninett.no/">UNINETT AS</a>
 
                 <br style="clear: right" />