fix: wx.showModal的title不能为undefined，否则不会弹窗

package.json

@@ -1,6 +1,6 @@
 {
   "name": "we-request",
-  "version": "1.6.5",
+  "version": "1.6.6",
   "description": "本工具通过拓展小程序的wx.request，让开发者通过简单的配置，实现自动管理登录态等功能",
   "keywords": [
     "登录态",

src/module/errorHandler.ts

@@ -52,7 +52,7 @@ function doError(title: string, content: string, retry?: () => any) {
     // 是否显示重试按钮
     const showErrorRetryBtn = config.errorRetryBtn && typeof retry === "function";
     wx.showModal(Object.assign({
-        title,
+        title: title || "",
         content: content || "网络或服务异常，请稍后重试",
     }, !showErrorRetryBtn ? {
         showCancel: false