tox 4 renamed a tox.ini configuration keyword and has slightly changed quoting behavior.

Also tox >= 3.18 supports the renamed keyword - https://tox.wiki/en/3.27.1/changelog.html#v3-18-0-2020-07-23

Also the changed quote works with both versions.

Component: packages: standard

Author: Matthias Koeppe, Frédéric Chapoton

Branch/Commit: 70da140

Reviewer: Frédéric Chapoton, Matthias Koeppe

Issue created by migration from https://trac.sagemath.org/ticket/34839