-r requirements.txt
mock
nose
sure==1.4.11
coverage
flake8==3.5.0
freezegun
flask
boto>=2.45.0
boto3>=1.4.4
botocore>=1.12.13
six>=1.9
parameterized>=0.7.0
prompt-toolkit==1.0.14
click==6.7
inflection==0.3.1
lxml==4.2.3
beautifulsoup4==4.6.0

-r requirements.txt
mock
nose
sure==1.4.11
coverage
flake8==3.7.8
freezegun
flask
boto>=2.45.0
boto3>=1.4.4
botocore>=1.12.13
six>=1.9
parameterized>=0.7.0
prompt-toolkit==1.0.14
click==6.7
inflection==0.3.1
lxml==4.2.3
beautifulsoup4==4.6.0

Use new flake8 for Python 3.8 compatibility
Use new flake8 for Python 3.8 compatibility

With the current flake8, which depends on pyflakes<1.7.0,>=1.5.0,
linting fails with:

AttributeError: 'FlakesChecker' object has no attribute 'CONSTANT'

The issue is fixed in pyflakes 2.1.0 [1]. Let's just use the latest
flake8.

[1] https://github.com/PyCQA/pyflakes/commit/7c74ab0ddccb60a9154c2af5aa4ee4581ccada4a
