fix crypto-js inclusion

Following https://github.com/brix/crypto-js#usage-without-requirejs

index.html

@@ -11,7 +11,7 @@
         />
         <link rel="icon" href="favicon.ico" />
          <script src="https://cdn.jsdelivr.net/npm/xterm@4.19.0/lib/xterm.min.js"></script>
-         <script src="https://cdn.jsdelivr.net/npm/crypto-js@4.1.1/index.min.js"></script>
+         <script src="https://cdn.jsdelivr.net/npm/crypto-js@4.1.1/crypto-js.js"></script>
          <script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
          <script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.4.1/js/bootstrap.min.js"></script>
     </head>