Adding style tools to CI

[jay-tyler]

Let's see if I broke CI...

[jay-tyler]

vulture is going to break, but I'm not 100% sure what to do for the following:

hug/decorators.py:160: unused variable 'req_succeeded' (100% confidence)
hug/decorators.py:182: unused variable 'req_succeeded' (100% confidence)
hug/middleware.py:92: unused variable 'req_succeeded' (100% confidence)
hug/middleware.py:141: unused variable 'req_succeeded' (100% confidence)
hug/middleware.py:179: unused variable 'req_succeeded' (100% confidence)

The req_succeeded arg isn't being passed through, but maybe it's there to

1. to satisfy an interface?
2. maintain backwards compatibility?

[timothycrosley]

This is looking great! Correct: It's there to satisfy Falcon's interface: https://falcon.readthedocs.io/en/stable/api/middleware.html - not sure of the best way to let vulture know about this.