fix import ordering

pkgs/glob/lib/src/list_tree.dart

diff --git a/pkgs/glob/lib/src/list_tree.dart b/pkgs/glob/lib/src/list_tree.dart
index 5339b58..f51e4bb 100644
--- a/pkgs/glob/lib/src/list_tree.dart
+++ b/pkgs/glob/lib/src/list_tree.dart
@@ -2,8 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-import 'dart:io';
 import 'dart:async';
+import 'dart:io';
 
 import 'package:async/async.dart';
 import 'package:path/path.dart' as p;