Bump pytest to 3.6.4 and pytest-flake8 to 1.0.2.
Bump pytest to 3.6.4 and pytest-flake8 to 1.0.2.

MozillaSecurity/funfuzz,MozillaSecurity/funfuzz,nth10sd/funfuzz,nth10sd/funfuzz,nth10sd/funfuzz,MozillaSecurity/funfuzz