contrib/python-zstandard/MANIFEST.in

cleanup: turn `wrapfunction` deprecation warning into an error

We could simply drop the check, but lets raise explicit error instead of
suffering strange error in case of misuse.

graft c-ext
graft debian
graft zstd
graft tests
include make_cffi.py
include setup_zstd.py
include zstd.c
include LICENSE
include NEWS.rst