Fix update to bootstrap 5.3.0-alpha

Change-Id: I1cc218e4c697a3caff0ee7f8060cd7dbc1e0850f
diff --git a/templates/header.htm b/templates/header.htm
index 119cc9b..38c37eb 100644
--- a/templates/header.htm
+++ b/templates/header.htm
@@ -5,7 +5,6 @@
     <!-- Required meta tags -->
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
-    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" integrity="sha384-ggOyR0iXCbMQv3Xipma34MD+dH/1fQ784/j6cY/iJTQUOhcWr7x9JvoRxT2MZw1T" crossorigin="anonymous">
     <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0-alpha1/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-GLhlTQ8iRABdZLl6O3oVMWSktQOp6b7In1Zl3/Jr59b6EGGoI1aFkw7cmDA6j6gD" crossorigin="anonymous">
     <title>Sign up for <?php echo $SERVICE_ACRONYM; ?></title>
     <link href="//netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap-glyphicons.css" rel="stylesheet">