Bump pyflakes to 2.2.0

This release includes PyCQA/pyflakes#455

Author: twm

tox.ini

@@ -126,8 +126,7 @@ deps =
     pep8-naming==0.11.1
     pycodestyle==2.6.0
     pydocstyle==5.1.1
-    # pin pyflakes pending a release with https://github.com/PyCQA/pyflakes/pull/455
-    git+git://github.com/PyCQA/pyflakes@ffe9386#egg=pyflakes
+    pyflakes==2.2.0
 
 commands =
     flake8 {posargs:setup.py src/{env:PY_MODULE}}