Update to flake8 3.6.0 (#2547)

* Update to flake8 3.6.0

* Configure line length and move to 'nice to have'

* Also update flake8-bugbear and pin flake8-pyi

.flake8

@@ -3,7 +3,6 @@
 # 17952 E704 multiple statements on one line (def)
 # 12197 E301 expected 1 blank line
 #  7155 E302 expected 2 blank lines
-#  2307 E501 line too long
 #  1463 F401 imported but unused
 #   967 E701 multiple statements on one line (colon)
 #   457 F811 redefinition
@@ -13,11 +12,17 @@
 # Nice-to-haves ignored for now
 #   159 E128 continuation line under-indented for visual indent
 #    34 E127 continuation line over-indented for visual indent
+#       E252 missing whitespace around parameter equals
+#  2307 E501 line too long
+
+# Other ignored warnings
+#       W504 line break after binary operator
 
 [flake8]
-ignore = F401, F403, F405, F811, E127, E128, E301, E302, E305, E501, E701, E704, E741, B303
+ignore = F401, F403, F405, F811, E127, E128, E252, E301, E302, E305, E501, E701, E704, E741, B303, W504
 # We are checking with Python 3 but many of the stubs are Python 2 stubs.
 # A nice future improvement would be to provide separate .flake8
 # configurations for Python 2 and Python 3 files.
 builtins = StandardError,apply,basestring,buffer,cmp,coerce,execfile,file,intern,long,raw_input,reduce,reload,unichr,unicode,xrange
 exclude = .venv*,@*,.git
+max-line-length = 130

requirements-tests-py3.txt

@@ -1,6 +1,6 @@
 git+https://github.com/python/mypy.git@master
 typed-ast>=1.0.4
-flake8==3.5.0
-flake8-bugbear==18.2.0
-flake8-pyi>=18.3.1
+flake8==3.6.0
+flake8-bugbear==18.8.0
+flake8-pyi==18.3.1
 pytype>=2018.9.19