Check if user-specified package name exists on PyPI already, and suggest an alternative one if it does

[webyneter]

Given the user-specified project name matches the one used for PyPI deployments (which is the out-of-box setup, by the way) inadvertent name clashes are possible:

$ twine upload dist/*                                          
Uploading distributions to https://upload.pypi.org/legacy/
Enter your username: ...
Enter your password: 
Uploading ....whl
100%|███████████████████████████████████████████████████████████████████████████████████████████████████████████████| 10.7k/10.7k [00:01<00:00, 8.48kB/s]
HTTPError: 403 Client Error: The user '...' isn't allowed to upload to project '...'. See https://pypi.org/help/#project-name for more information. for url: https://upload.pypi.org/legacy/

Not sure if the proposal is relevant in terms of overall project roadmap though.