成功解决：You are using pip version 10.0.1, however version 20.0.2 is available.

今天使用pip安装Pillow时出现问题：

You are using pip version 10.0.1, however version 20.0.2 is available.
You should consider upgrading via the ‘python -m pip install --upgrade pip’ command.
然后试了别人说的完美解决的方法：python -m pip install -U pip

试了一次没有用又试了很久都没有用，然后又试原来那个python -m pip install --upgrade pip好几次，都没用

最后终于找到了成功的方法:

python -m pip install --upgrade pip -i https://pypi.douban.com/simple