使用pip安装插件的时候报错：
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the ‘python -m pip install --upgrade pip‘ command.
升级命令
python -m pip install --upgrade pip
原文：https://www.cnblogs.com/jyiqing/p/9313854.html