Log Message:
py-flit_core py-flit: updated to 3.7.1

Version 3.7.1

Fix building packages which need execution to get the version number, and have a \ 
relative import in __init__.py.

Version 3.7

Support for external data files such as man pages or Jupyter extension support files.
Project names are now lowercase in wheel filenames and .dist-info folder names, \ 
in line with the specification.
Improved support for bootstrapping a Python environment, e.g. for downstream \ 
packagers. flit_core.wheel is usable with python -m to create wheels before the \ 
build tool is available, and flit_core sdists also include a script to install \ 
itself from a wheel before installer is available.
Use newer importlib APIs, fixing some deprecation warnings