Possible fix typo in README

[amandasaurus]

I think this is a typo in the README.

$ ./venv/bin/pip --no-build-isolation --config-settings=editable.rebuild=true -Cbuild-dir=/tmp/build -ve.

Usage:   
  pip <command> [options]

no such option: --no-build-isolation

but when I do it as pip install, I get Proper Looking™ results