Use Python 3.7 for invoking tox.
@@ -13,8 +13,8 @@ basepython =
pypypy3.5: pypy3.5
pypypy3: pypy3
{py3.5,py3.5-dist,py3.5-dist-wheel}: python3.5
- {py3.6,py3.6-dist,py3.6-dist-wheel,black,black-check}: python3.6
- {py3.7,docs,checks,lint,pylint,mypy,coverage,docs,py3.7-dist,py3.7-dist-wheel}: python3.7
+ {py3.6,py3.6-dist,py3.6-dist-wheel}: python3.6
+ {py3.7,docs,checks,lint,pylint,mypy,coverage,docs,py3.7-dist,py3.7-dist-wheel,black,black-check}: python3.7
{py3.8,py3.8-windows,integration-storage,py3.8-dist,py3.8-dist-wheel}: python3.8
{py3.9,py3.9-dist,py3.9-dist-wheel}: python3.9
{py3.10,py3.10-dist,py3.10-dist-wheel}: python3.10
