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

pkg/http/test/utils.dart

Index: pkg/http/test/utils.dart
diff --git a/pkg/http/test/utils.dart b/pkg/http/test/utils.dart
index 6bbe139a7adbc856d7ec3b1b9603f67a225342c3..ab3f5f6dfdebeb1e67fb23d7bdbea7807c920d66 100644
--- a/pkg/http/test/utils.dart
+++ b/pkg/http/test/utils.dart
@@ -9,10 +9,11 @@ import 'dart:io';
 import 'dart:json' as json;
 import 'dart:uri';
 
+import 'package:http/http.dart' as http;
+import 'package:http/src/byte_stream.dart';
+import 'package:http/src/utils.dart';
 import 'package:unittest/unittest.dart';
-import '../lib/src/byte_stream.dart';
-import '../lib/http.dart' as http;
-import '../lib/src/utils.dart';
+
 import 'safe_http_server.dart';
 
 /// The current server instance.