Serve web manifest with manifest MIME type

dist/default.conf

@@ -17,6 +17,11 @@ server {
     proxy_set_header X-Forwarded-Proto $scheme;
   }
 
+  location = /manifest.webmanifest {
+    default_type application/manifest+json;
+    try_files $uri =404;
+  }
+
   location / {
     try_files $uri $uri/ /index.html;
   }