修改 cqhttp 的发送的数据类型为 JSON ，避免使用表单可能出现的转码问题 (#543)

Co-authored-by: shaochuan.wu <shaochuan.wu@fit2cloud.com>

sample/notify.js

@@ -208,9 +208,9 @@ function gobotNotify(text, desp, time = 2100) {
     if (GOBOT_URL) {
       const options = {
         url: `${GOBOT_URL}?access_token=${GOBOT_TOKEN}&${GOBOT_QQ}`,
-        body: `message=${text}\n${desp}`,
+        json: {message:`${text}\n${desp}`},
         headers: {
-          'Content-Type': 'application/x-www-form-urlencoded',
+          'Content-Type': 'application/json',
         },
         timeout,
       };