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

utils/tests/pub/validator_test.dart

Index: utils/tests/pub/validator_test.dart
diff --git a/utils/tests/pub/validator_test.dart b/utils/tests/pub/validator_test.dart
index 12dbd8287a7ac325e92421222ceb5ad1ad67a677..2e886592a8979b8d26c053b89084596ea7b6f954 100644
--- a/utils/tests/pub/validator_test.dart
+++ b/utils/tests/pub/validator_test.dart
@@ -9,10 +9,10 @@ import 'dart:io';
 import 'dart:json' as json;
 import 'dart:math' as math;
 
-import '../../../pkg/http/lib/http.dart' as http;
-import '../../../pkg/http/lib/testing.dart';
-import '../../../pkg/pathos/lib/path.dart' as path;
-import '../../../pkg/scheduled_test/lib/scheduled_test.dart';
+import 'package:http/http.dart' as http;
+import 'package:http/testing.dart';
+import 'package:pathos/path.dart' as path;
+import 'package:scheduled_test/scheduled_test.dart';
 
 import '../../pub/entrypoint.dart';
 import '../../pub/io.dart';