`PKG-INFO` in sdist is missing `License-File`

[mtelka]

The sdist package contains license in docs/license.txt, but the package metadata does not point there. It would be great if either the PKG-INFO contains something like (see PEP 639):

License-File: docs/license.txt

or the license is moved to LICENSE file.

Thank you.

[mtelka]

This is probably related to #67.

[mtelka]

I think this contains some hints how to do that.

[cdent]

Fixed in #100