Add example

pkgs/package_config/example/main.dart

diff --git a/pkgs/package_config/example/main.dart b/pkgs/package_config/example/main.dart
new file mode 100644
index 0000000..42a5963
--- /dev/null
+++ b/pkgs/package_config/example/main.dart
@@ -0,0 +1,18 @@
+// Copyright (c) 2020, the Dart project authors.  Please see the AUTHORS file
+// 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:package_config/package_config.dart';
+import 'dart:io' show Directory;
+
+void main() async {
+  var packageConfig = await findPackageConfig(Directory.current);
+  if (packageConfig == null) {
+    print('Failed to locate or read package config.');
+  } else {
+    print('This package depends on ${packageConfig.packages.length} packages:');
+    for (var package in packageConfig.packages) {
+      print('- ${package.name}');
+    }
+  }
+}