use __invoke when no method set for the action

Author: rizqyhi

src/Illuminate/Routing/Router.php

@@ -992,9 +992,9 @@ protected function getClassClosure($controller)
 			// Now we can split the controller and method out of the action string so that we
 			// can call them appropriately on the class. This controller and method are in
 			// in the Class@method format and we need to explode them out then use them.
-			[$class, $method] = explode('@', $controller);
+            $classAndMethod = explode('@', $controller);
 
-			return $d->dispatch($route, $request, $class, $method);
+            return $d->dispatch($route, $request, $classAndMethod[0], $classAndMethod[1] ?? '__invoke');
 		};
 	}