PyPi upload command is deprecated.

The 'deploy_pypi' CI job raises the following warning:

Writing arosics-0.8.15/setup.cfg
creating dist
Creating tar archive
removing 'arosics-0.8.15' (and everything under it)
running upload
Password: 
WARNING: Uploading via this command is deprecated, use twine to upload instead (https://pypi.org/p/twine/)