Update tox from 3.4.0 to 3.5.2
Update tox from 3.4.0 to 3.5.2
chrisdev/wagtail-cookiecutter-foundation,ilendl2/wagtail-cookiecutter-foundation,ilendl2/wagtail-cookiecutter-foundation,chrisdev/wagtail-cookiecutter-foundation,chrisdev/wagtail-cookiecutter-foundation,ilendl2/wagtail-cookiecutter-foundation