Log Message:
py-flit: update to 3.11.0.

Version 3.11
------------

- Support for SPDX license expressions and multiple license files, as detailed
  in :pep:`639`::

        license = "BSD-3-Clause"
        license-files = ["LICENSE"]

  For now, only a single license identifier is allowed. More complex expressions
  describing multiple licenses & expressions may be supported in a future
  version.
- The `metadata format \ 
<https://packaging.python.org/en/latest/specifications/core-metadata/>`_
  in produced packages is now version 2.4, to support the expanded license
  information.