chore: add the change logs for #9705

changes/v5.0.14/fix-9705.en.md

@@ -0,0 +1,8 @@
+Remove the default value of Webhook.
+Before this repair, the default value of the `body` field of Webhook is `${payload}`,
+but there is no `payload` field in the available fields of other events except message
+publishing in the rule, so in this case, the webhook will send a string with the
+message body as "undefined" to the HTTP service.
+This fix removes the default value of the `body` field. When the `body` field is
+not configured, Webhook will send all available fields of the current event in
+the format of JSON object.

changes/v5.0.14/fix-9705.zh.md

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+删除 Webhook 的默认值。
+在此修复之前，Webhook 的 `body` 字段的默认值为 `${payload}`，但规则中除了消息发布之外的其他事件的可用字段中
+都没有 `payload` 字段，所以这种情况下 Webhook 将发送消息正文为 "undefined" 的字符串到 HTTP 服务。
+此修复移除了 `body` 字段的默认值，当未配置 `body` 字段的时候，Webhook 将以 JSON object 的格式发送
+当前事件的全部可用字段。