Switch pkg packages, pub, and dartdoc to use package: imports.

utils/tests/pub/install/path/path_is_file_test.dart

Index: utils/tests/pub/install/path/path_is_file_test.dart
diff --git a/utils/tests/pub/install/path/path_is_file_test.dart b/utils/tests/pub/install/path/path_is_file_test.dart
index 75fc8baf6bb334af18851a4052b515d87fc11a58..96355754635a3a525f81e1c49a5847491893af38 100644
--- a/utils/tests/pub/install/path/path_is_file_test.dart
+++ b/utils/tests/pub/install/path/path_is_file_test.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 d.file.
 
-import '../../../../../pkg/pathos/lib/path.dart' as path;
-import '../../../../../pkg/scheduled_test/lib/scheduled_test.dart';
+import 'package:pathos/path.dart' as path;
+import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../../../pub/exit_codes.dart' as exit_codes;
 import '../../descriptor.dart' as d;