changed bootstrap link

templates/index.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <title>CHRIS</title>
 <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
-<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
+<script src="https://cdn.jsdelivr.net/npm/bootstrap@3.4.1/dist/js/bootstrap.min.js" integrity="sha384-aJ21OjlMXNL5UyIl/XNwTMqvzeRMZH2w8c5cRVpzpU8Y5bApTppSuUkhZXN0VxHd" crossorigin="anonymous"></script>
 <style>
 body {font-family: Arial, Helvetica, sans-serif;}