add tox config to check pre-commit rules

pyproject.toml

@@ -7,4 +7,15 @@ exclude = '''
     \.git
   | \.tox
 )/
-'''
+'''
+
+[tool.tox]
+legacy_tox_ini = '''
+[tox]
+envlist = style
+
+[testenv:style]
+deps =
+	pre-commit
+commands = pre-commit run --all-files
+'''