Merge pull request #4099 from asottile/re-enable_linting_windows

re-enable linting tox env on windows

.pre-commit-config.yaml

@@ -1,7 +1,7 @@
 exclude: doc/en/example/py2py3/test_py2.py
 repos:
 -   repo: https://github.com/ambv/black
-    rev: 18.9b0
+    rev: 18.6b4
     hooks:
     -   id: black
         args: [--safe, --quiet]

appveyor.yml

@@ -1,5 +1,7 @@
 environment:
   matrix:
+  - TOXENV: "linting"
+    PYTEST_NO_COVERAGE: "1"
   - TOXENV: "py27"
   - TOXENV: "py34"
   - TOXENV: "py35"

src/_pytest/config/__init__.py

@@ -423,7 +423,7 @@ class PytestPluginManager(PluginManager):
                     and not self._using_pyargs
                 ):
                     from _pytest.deprecated import (
-                        PYTEST_PLUGINS_FROM_NON_TOP_LEVEL_CONFTEST,
+                        PYTEST_PLUGINS_FROM_NON_TOP_LEVEL_CONFTEST
                     )
 
                     warnings.warn_explicit(