Add a 512x512 icon to the web app manifest

public/manifest.json

@@ -29,6 +29,11 @@
       "src": "/images/webapp-icon-256.png",
       "sizes": "256x256",
       "type": "image/png"
+    },
+    {
+      "src": "/images/webapp-icon-512.png",
+      "sizes": "512x512",
+      "type": "image/png"
     }
   ]
 }