icon 깨짐 방지

frontend/web/index.html

@@ -31,6 +31,7 @@
 
   <title>frontend</title>
   <link rel="manifest" href="manifest.json">
+  <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
 </head>
 <body>
   <script src="flutter_bootstrap.js" async></script>