[ffigen] Increase timeout Flutter integration test (#446)

pkgs/ffigen/test_flutter/flutter_template_tests/flutter_plugin_ffi_test.dart

diff --git a/pkgs/ffigen/test_flutter/flutter_template_tests/flutter_plugin_ffi_test.dart b/pkgs/ffigen/test_flutter/flutter_template_tests/flutter_plugin_ffi_test.dart
index 9f74c81..06b9df7 100644
--- a/pkgs/ffigen/test_flutter/flutter_template_tests/flutter_plugin_ffi_test.dart
+++ b/pkgs/ffigen/test_flutter/flutter_template_tests/flutter_plugin_ffi_test.dart
@@ -2,6 +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 file.
 
+@Timeout(Duration(seconds: 120))
+
 import 'dart:convert';
 import 'dart:io';