[REM] packaging: remove useless winpy_requirements.txt file

As this file was only used as a one shot for the windows pacakging, it
can be removed from the code.

closes odoo/odoo#54843

X-original-commit: 551587e1bc8a9c6d27be782c7e553189603af3fb
Signed-off-by: Christophe Monniez (moc) <moc@odoo.com>