cmd/ursrv: Update map tile URL

cmd/ursrv/serve/static/index.html

@@ -197,7 +197,7 @@ found in the LICENSE file.
       };
 
       var baseLayer = L.tileLayer(
-        'https://{s}.tile.openstreetmap.org/{z}/{x}/{y}.png',{
+        'https://tile.openstreetmap.org/{z}/{x}/{y}.png',{
           attribution: '...',
           maxZoom: 18
         }