add more metadata

assets/manifest.json

@@ -3,7 +3,7 @@
     "short_name": "Prismarine Web Client",
     "icons": [{
         "src": "favicon.png",
-        "sizes": "256x256"
+        "sizes": "512x512"
     }],
     "background_color": "#ffffff",
     "theme_color": "#ffffff",

index.html

@@ -5,6 +5,9 @@
     <link rel="stylesheet" href="styles.css">
     <link rel="favicon" href="favicon.ico">
     <link rel="icon" type="image/png" href="favicon.png" />
+    <meta name="description" content="Minecraft web client running in your browser">
+    <meta name="keywords" content="Minecraft, Web, Voxel, Javascript, PrismarineJS">
+    <meta name="author" content="PrismarineJS">
     <meta name="theme-color" content="#ffffff">
     <meta name='viewport' content='width=device-width, initial-scale=1.0, maximum-scale=1.0,user-scalable=0'>
     <meta property="og:title" content="Prismarine Web Client" />