switch from pytest-flake8 to raw flake8; clean up ignores

.flake8

@@ -0,0 +1,16 @@
+[flake8]
+ignore =
+    # Refers to the max-line length. Let's suppress the error and simply
+    # let black take care on how it wants to format the lines.
+    E501,
+
+    # Refers to "line break before/after binary operator".
+    # Similar to above, let black take care of the formatting.
+    W503,
+    W504,
+
+    # black disagrees with flake8, and inserts whitespace
+    E203,  # whitespace before ':'
+
+    # It seems flake8 can misfire on it
+    E401, # multiple imports on one line

pytest.ini

@@ -1,19 +1,2 @@
 [pytest]
 doctest_optionflags = ALLOW_UNICODE ALLOW_BYTES
-flake8-max-line-length = 88
-flake8-ignore =
-    W503  # https://www.flake8rules.com/rules/W503.html
-    E203  # https://www.flake8rules.com/rules/E203.html
-
-    docs/conf.py E121 E122 E265 E401
-    tests/test_encoding.py E128 E221 E241 E302 E401 E501 E731
-    tests/test_form.py E265
-    tests/test_html.py E123 E128 E241 E303 E501 E502
-    tests/test_http.py E128 E261 E302 W291
-    tests/test_url.py E126 E127 E128 E226 E261 E303 E501 W293 W391
-    w3lib/encoding.py E126 E128 E302 E305 E401 E501
-    w3lib/form.py E402 E501 E721
-    w3lib/html.py E128 E302 E501 E502 W504
-    w3lib/http.py E501
-    w3lib/url.py E128 E261 E302 E305 E501 F841 W291 W293 W504
-    w3lib/util.py E302

tests/test_encoding.py

@@ -280,7 +280,9 @@ def test_html_encoding(self):
         self._assert_encoding_detected(None, "utf-8", codecs.BOM_UTF8 + body)
 
     def test_autodetect(self):
-        asciif = lambda x: "ascii"
+        def asciif(x):
+            return "ascii"
+
         body = b"""<meta charset="utf-8">"""
         # body encoding takes precedence
         self._assert_encoding_detected(None, "utf-8", body, auto_detect_fun=asciif)

tox.ini

@@ -27,17 +27,20 @@ basepython = python3
 deps =
     # mypy would error if pytest (or its sub) not found
     pytest
-    mypy==0.910
+    mypy==0.971
 commands =
     mypy --show-error-codes {posargs: w3lib tests}
 
 [testenv:flake8]
 basepython = python3
 deps =
-    {[testenv]deps}
-    pytest-flake8
+    flake8
 commands =
-    pytest --flake8
+    flake8 \
+    w3lib \
+    setup.py \
+    tests \
+    {posargs}
 
 [testenv:pylint]
 deps =
@@ -48,7 +51,7 @@ commands =
 
 [testenv:black]
 deps =
-    black==22.3.0
+    black==22.6.0
 commands =
     black --check {posargs:conftest.py setup.py tests w3lib}