Following the lead from tox, use a simple Python script instead of depending
on ``invoke``.
Other changes:
* Some colors using ``colorama``.
* Run ``pre-commit`` before the final commit to ensure everything is neatly
formatted.
* Drop generating local tag: legacy from the time we used ``devpi`` as staging
area, currently we no longer use it, and we should push a
tag from the last HEAD of the PR always to ensure it is correct.
Because setuptools_scm already includes all version-controlled files
in an sdist, we don't need to maintain a MANIFEST.in file and anymore
See pytest-dev/pytest-xdist#161
Bruno Oliveira
Anthony Sottile
Ronny Pfannschmidt
Ronny Pfannschmidt