Actual "proper" install of ruamel.yaml in the windows CI
It was impossible to update the package directly with `pip`. Indeed it was installed with `distutils` which prevents `pip` or `conda` to uninstall it.

I had to `rm` a directory from the `site-packages` python directory, and then do `pip install ruamel.yaml`

It's not that "proper" but I couldn't find better solutions