fix index: try manifest.min.json

Try the minified manifest.min.json. But maybe it had to be the fixed
filename manifest.json.

Signed-off-by: Conrad Zelck <git@simpel.cc>

index.php

@@ -6,7 +6,7 @@
     <!-- <title>FreqBuddy</title> -->
     <script src="script.min.js" defer></script>
     <link rel="stylesheet" href="style.min.css">
-    <link rel="manifest" href="/manifest.json">
+    <link rel="manifest" href="/manifest.min.json">
     <link rel="apple-touch-icon" sizes="57x57" href="/icons/apple-icon-57x57.png">
     <link rel="apple-touch-icon" sizes="60x60" href="/icons/apple-icon-60x60.png">
     <link rel="apple-touch-icon" sizes="72x72" href="/icons/apple-icon-72x72.png">