New release of PyNeb: 1.1.23

[Christophe Morisset]

Dear PyNeb users,

I just published a new release of PyNeb 1.1.23, that should solve the issue meet by some users when installing PyNeb, with an error message of the type "Numpy not found".

This required the change in the way the package is build, we now use the pyproject.toml file to manage it.

Please note that I also change the way the Machine Learning facilities are used: you need to explicitly write pn.import_AI4Neb() before being able to use it. This allows users not interested in using the ML tools to quickly import pyneb without being annoyed by some Tensorflow messages.

I hope this fixes the issue, please report any problems.

Saludos,

Christophe