Add pre-commit hook for tox-ini-fmt

Format tox.ini automatically with a pre-commit hook

.pre-commit-config.yaml

@@ -53,3 +53,7 @@ repos:
     hooks:
     -   id: check-hooks-apply
     -   id: check-useless-excludes
+-   repo: https://github.com/tox-dev/tox-ini-fmt
+    rev: 0.5.1
+    hooks:
+    -   id: tox-ini-fmt

tox.ini

@@ -1,9 +1,20 @@
 [tox]
-envlist = py36,py37,py38,pypy3,pre-commit
+envlist =
+    py38
+    py37
+    py36
+    pypy3
+    pre-commit
 
 [testenv]
-deps = -rrequirements-dev.txt
-passenv = APPDATA HOME LOCALAPPDATA PROGRAMFILES RUSTUP_HOME
+passenv =
+    APPDATA
+    HOME
+    LOCALAPPDATA
+    PROGRAMFILES
+    RUSTUP_HOME
+deps =
+    -rrequirements-dev.txt
 commands =
     coverage erase
     coverage run -m pytest {posargs:tests}
@@ -11,8 +22,10 @@ commands =
 
 [testenv:pre-commit]
 skip_install = true
-deps = pre-commit
-commands = pre-commit run --all-files --show-diff-on-failure
+deps =
+    pre-commit
+commands =
+    pre-commit run --all-files --show-diff-on-failure
 
 [pep8]
 ignore = E265,E501,W504