Update flake8 from 3.7.5 to 3.7.7

pyup-bot · tony · commit 8b07e017d561 · 2019-03-12T09:59:27.000+01:00
diff --git a/requirements/dev.txt b/requirements/dev.txt
@@ -1,2 +1,2 @@
 isort==4.3.15
-flake8==3.7.5
+flake8==3.7.7
