阿里云会限速，可以用腾讯或者华为代替
官方
pip config list
global.index-url='https://pypi.org/simple'
global.timeout='60'
腾讯镜像
pip install -i https://mirrors.cloud.tencent.com/pypi/simple --upgrade pip
pip config set global.index-url https://mirrors.cloud.tencent.com/pypi/simple
恢复官网默认配置
pip install pip -U
pip config set global.index-url https://pypi.org/simple