Update tox to 3.17.1#1237

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

pyup-update-tox-3.5.3-to-3.17.1kragniz/python-etcd3:pyup-update-tox-3.5.3-to-3.17.1Copy head branch name to clipboard