安装icrawler时候运行如下命令
sudo pip install icrawler
报错：
Cannot uninstall 'requests'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall
这是就旧版本的requests 依赖比较多，pip不能准确找到依赖关系。
解决方式：忽略旧版本的依赖信息
运行如下命令：
sudo pip install icrawler --ignore-installed requests
