ERROR: After October 2020 you may experience errors when installing or updating packages.解决方法

在使用：

pip3 install -user --upgrade --force-reinstall --no-cache-dir jupyter

报错如下：
ERROR: After October 2020 you may experience errors when installing or updating packages. This is because pip will change the way that it resolves dependency conflicts.

解决方法

在命令后加上–use-feature=2020-resolver
即：

pip3 install -user --upgrade --force-reinstall --no-cache-dir jupyter --use-feature=2020-resolver