Use latest version in demo

Author: lucaong

examples/plain_js/index.html

@@ -88,7 +88,7 @@ <h1>Song Search</h1>
         </article>
       </div>
     </div>
-    <script src="https://cdn.jsdelivr.net/npm/minisearch@7.0.2/dist/umd/index.min.js"></script>
+    <script src="https://cdn.jsdelivr.net/npm/minisearch@7.1.0/dist/umd/index.min.js"></script>
     <script src="app.js" type="text/javascript"></script>
   </body>
 </html>