Update tox to 4.2.1#2067

pyup-bot wants to merge 1 commit intomasterkragniz/python-etcd3:masterfrom

pyup-update-tox-3.23.1-to-4.2.1kragniz/python-etcd3:pyup-update-tox-3.23.1-to-4.2.1Copy head branch name to clipboard