fix UPnP listing updates not appearing until manual table view scolling due to background delegate callback

Sources/LocalNetworkConnectivity/ServerBrowsing/VLCNetworkServerBrowserUPnP.m

@@ -76,7 +76,9 @@
         }
 
         self.items = [itemsArray copy];
-        [self.delegate networkServerBrowserDidUpdate:self];
+        [[NSOperationQueue mainQueue] addOperationWithBlock:^{
+            [self.delegate networkServerBrowserDidUpdate:self];
+        }];
     }];
 }