Add registration closing

Change-Id: I3b9507e7329f8b163b8cb6ef97755f9102734c41
diff --git a/templates/register.htm b/templates/register.htm
index 30d9707..5820d00 100644
--- a/templates/register.htm
+++ b/templates/register.htm
@@ -485,6 +485,7 @@
                         echo '<input type="hidden" name="conference_fee" value="' . $REGULAR_CONFERENCE_FEE . '">';
                         echo '<input type="hidden" name="earlybird_registration" value="">';
                     } ?>
+                    Registration will close after <?php echo $REGISTRATION_DEADLINE; ?>.
             </label>
             <div class="invalid-feedback">
                 You need to confirm your participation in order to proceed.