Update wechat_response.dart

bugfix: 微信登录没回调bug修复

Update wechat_response.dart
db8d6d73 · 瑞宇 · GitHub · a798ea1d · db8d6d73
--- a/lib/src/response/wechat_response.dart
+++ b/lib/src/response/wechat_response.dart
@@ -46,7 +46,7 @@ Map<String, _WeChatResponseInvoker> _nameAndResponseMapper = {
 class BaseWeChatResponse {
  final int errCode;
-  final String errStr;
+  final String? errStr;
  bool get isSuccessful => errCode == 0;