Use "package:" imports for pub.

test/validator/pubspec_field_test.dart

Index: test/validator/pubspec_field_test.dart
diff --git a/test/validator/pubspec_field_test.dart b/test/validator/pubspec_field_test.dart
index 4f0f33ec9501b67528b2416692ed35d1c243a81c..3af75efc1013973402de985d17f56eca6c9cafe6 100644
--- a/test/validator/pubspec_field_test.dart
+++ b/test/validator/pubspec_field_test.dart
@@ -2,11 +2,11 @@
 // 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 'package:pub/src/entrypoint.dart';
+import 'package:pub/src/validator.dart';
+import 'package:pub/src/validator/pubspec_field.dart';
 import 'package:scheduled_test/scheduled_test.dart';
 
-import '../../lib/src/entrypoint.dart';
-import '../../lib/src/validator.dart';
-import '../../lib/src/validator/pubspec_field.dart';
 import '../descriptor.dart' as d;
 import '../test_pub.dart';
 import 'utils.dart';