Update pep8-naming compatibility with flake8 (#210)

`pep8-naming` tests fail for `flake8` v3/v4; avoid suggesting that it works 

Additionally, v6 added one more required `kwarg`. Let's add that one too.

run_tests.py

@@ -72,10 +72,17 @@ def load_tests(lines):
 
 def parse_options(checker, options):
     """Parse the CLI-style flags from `options` and expose to `checker`"""
+    extra_kwargs = {}
+    if flake8.__version_info__[0] >= 6:
+        extra_kwargs = {
+            "formatter_names": []
+        }
+
     options_manager = OptionManager(
         version=flake8.__version__,
         plugin_versions=f"naming: {pep8ext_naming.__version__}",
         parents=[],
+        **extra_kwargs,
     )
     options_manager.add_option('--select', default=[])
     options_manager.add_option('--extended-default-select', default=['N'])

setup.py

@@ -42,7 +42,7 @@ def run_tests(self):
     license='Expat license',
     package_dir={'': 'src'},
     py_modules=['pep8ext_naming'],
-    install_requires=['flake8>=3.9.1'],
+    install_requires=['flake8>=5.0.0'],
     zip_safe=False,
     python_requires='>=3.7',
     entry_points={

tox.ini

@@ -1,5 +1,11 @@
 [tox]
-envlist = py37,py38,py39,py310,py310-flake8,pypy3
+envlist =
+    py37-flake85,
+    py38-flake8-{v5,v6,latest},
+    py39-flake8-{v5,v6,latest},
+    py310-flake8-{v5,v6,latest},
+    py310-flake8,
+    pypy3
 
 [gh-actions]
 python =
@@ -12,7 +18,9 @@ python =
 [testenv]
 commands = python run_tests.py
 deps =
-    flake8 >= 5.0.0
+    flake8-v5: flake8 >= 5.0.0, < 6.0.0
+    flake8-v6: flake8 >= 6.0.0, < 7.0.0
+    flake8-latest: flake8
 
 [testenv:py310-flake8]
 basepython = python3.10