Update non-required dependencies

Author: mdmintz

requirements.txt

@@ -92,6 +92,6 @@ pytest-cov==2.11.1
 flake8==3.7.9;python_version<"3.5"
 flake8==3.9.0;python_version>="3.5"
 pyflakes==2.1.1;python_version<"3.5"
-pyflakes==2.3.0;python_version>="3.5"
+pyflakes==2.3.1;python_version>="3.5"
 pycodestyle==2.5.0;python_version<"3.5"
 pycodestyle==2.7.0;python_version>="3.5"

setup.py

@@ -200,7 +200,7 @@
             'flake8==3.7.9;python_version<"3.5"',
             'flake8==3.9.0;python_version>="3.5"',
             'pyflakes==2.1.1;python_version<"3.5"',
-            'pyflakes==2.3.0;python_version>="3.5"',
+            'pyflakes==2.3.1;python_version>="3.5"',
             'pycodestyle==2.5.0;python_version<"3.5"',
             'pycodestyle==2.7.0;python_version>="3.5"',
         ],