`setuptools` & `pip` whl files were selected via wildcards, because it was
easier in the beginning.
Also, initially there weren't any PYTHON{3}_{SETUTPTOOLS/PIP}_VERSION
variables. But now since these vars exist, it makes sense to use them,
because we can catch easier (at build) time if Python/Python3 bump these
versions.

Signed-off-by: Alexandru Ardelean <ardeleanalex@gmail.com>