Merge pull request #969 from adamtheturtle/pyup-update-flake8-3.7.6-to-3.7.7

Update flake8 to 3.7.7

Author: adamtheturtle

dev-requirements.txt

@@ -6,7 +6,7 @@ dodgy==0.1.9  # Look for uploaded secrets
 dulwich==0.19.11
 flake8-commas==2.0.0  # Require silicon valley commas
 flake8-quotes==1.0.0  # Require single quotes
-flake8==3.7.6  # Lint
+flake8==3.7.7  # Lint
 isort==4.3.4  # Lint imports
 mypy-mypyc==0.670  # Type checking
 pip_check_reqs==2.0.3