Use pyproject.toml instead of setup.py

[bastiencyr]

Hello,

I have rewritten the setup.py into pyproject.toml.
The build result is exactly the same.
However:

1. I have removed the licence keyword since it is not needed thanks to trove classifier : https://setuptools.pypa.io/en/latest/deprecated/distutils/setupscript.html#additional-meta-data
2. I have added the black profile just in case you use black : https://black.readthedocs.io/en/stable/guides/using_black_with_other_tools.html
3. I have changed the version value from 0.5.0 to 0.5.1

[bastiencyr]

Should close #20