Validate-pyproject

===========

- ``setuptools`` plugin:
- Added support for ``readme``, ``license`` and ``license-files`` via ``dynamic``.

.. warning::
``license`` and ``license-files`` in ``dynamic`` are **PROVISIONAL**
they are likely to change depending on :pep:`639`

- Removed support for ``tool.setuptools.dynamic.{scripts,gui-scripts}``.
Dynamic values for ``project.{scripts,gui-scripts}`` are expected to be
dynamically derived from ``tool.setuptools.dynamic.entry-points``.

===========

- ``setuptools`` plugin:
- Added ``cmdclass`` support

===========

- ``setuptools`` plugin:
- Added ``data-files`` support (although this option is marked as deprecated).
- Unified ``tool.setuptools.packages.find`` and ``tool.setuptools.packages.find-namespace``
options by adding a new keyword ``namespaces``
- ``tool.setuptools.packages.find.where`` now accepts a list of directories
(previously only one directory was accepted).

=============

- Initial release with basic functionality