首先MIPCMS熊掌号默认调用publish_time， 代码如下：
...
"description": "{$mipDescription}",
"pubDate": "{$itemInfo['publish_time']|date='Y-m-d',###}T{$itemInfo['publish_time']|date='H:i:s',###}",
"isOriginal": "1"
...MIPCMS文章发布的时间是：publish_time 而文章更新的时间是：create_time
