python3-flit: Update to version 3.7.1

python3-flit: Update to version 3.7.1

- Update from 3.6.0 to 3.7.1
- Update of rootfile
- Changelog
	Version 3.7.1
	    Fix building packages which need execution to get the version number, and
             have a relative import in __init__.py (PR #531).
	Version 3.7
	    Support for external data files such as man pages or Jupyter extension
             support files (PR #510).
	    Project names are now lowercase in wheel filenames and .dist-info folder
             names, in line with the specifications (PR #498).
	    Improved support for bootstrapping a Python environment, e.g. for downstream
             packagers (PR #511). 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 (PR #499).

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>