support pep621

[graingert]

pep621 is now publicly supported and documented in flit, zest.releaser should support it also by setting the pyproject.toml :

[project]
version = "0.0.0a0"

field

(While preserving quote type too)

[graingert]

Also if zest sees this field it should take priority over any version in any other location, eg setup.py/cfg

[regebro]

I looked into this a bit more, and I think supporting this doesn't really make any sense unless zest.releaser also supports building the package with flit, so in essence I think this really is fully a part of #295.

[graingert]

Setuptools 61 now supports PEP 621 (and setup.cfg is pending deprecation)

[mauritsvanrees]

Version 8.0.0a1 supports writing the version to pyproject.toml.
For releasing you still need a setup.py for now. currently zest.releaser simply checks if there is a setup.py. If it is not there, zest.releaser does not create distributions, and does not push to PyPI. That will hopefully be for later in the alpha stage.