Update index.html

网页图标改用 32px 和 192px 的小图。

website/templates/index.html

@@ -7,7 +7,8 @@
   <meta name="theme-color" content="#f3f2ee" media="(prefers-color-scheme: light)">
   <meta name="theme-color" content="#1a1d1c" media="(prefers-color-scheme: dark)">
   <title>CS-Notes · CyC2018</title>
-  <link rel="icon" href="/favicon.png">
+  <link rel="icon" href="/icons/favicon-32.png" sizes="32x32">
+  <link rel="icon" href="/icons/icon-192.png" sizes="192x192">
   <link rel="apple-touch-icon" href="/icons/icon-180.png">
   <link rel="manifest" href="/manifest.webmanifest">
   <meta property="og:type" content="website">