Add flake8 pydocstyle. (#893)

Author: janiversen

requirements.txt

@@ -70,6 +70,7 @@ flake8-comprehensions
 isort
 pep8
 pyflakes
+pydocstyle
 pylint
 pytest
 pytest-cov

setup.cfg

@@ -470,15 +470,15 @@ max-complexity  = 25
 doctests        = True
 max-line-length = 120
 # To work with Black 
+# D202 No blank lines allowed after function docstring
+# E203: Whitespace before ':'
 # E501: line too long
 # W503: Line break occurred before a binary operator
-# E203: Whitespace before ':'
-# D202 No blank lines allowed after function docstring
 # W504 line break after binary operator
 ignore =
     D202,
-    E501,
     E203,
+    E501,
     W503,
     W504,