Remove outdated argparse dependency

[IGassmann]

The argparse library is included in Python 2.7 and in Python 3 since version 3.2, see https://pypi.org/project/argparse/.

The argparse PyPI library version isn't up-to-date anymore with the built-in version. It causes issues for apps that depend on df2gspread and that also use more recent capabilities of argparse since df2gspread overrides Python built-in version with an older version. See https://stackoverflow.com/questions/55619099/django-admin-typeerror-init-got-an-unexpected-keyword-argument-allow-abb