setup: bump version numbers to current max This will most likely give best py3 support, and we need thorough testing anyway. Based on 'pip freeze' before/after: sed -i '/>=[^#]*$/s/, < [0-9.]\+//g' setup.py dev_requirements.txt

pytest >= 4.6.6, < 5.4
pytest-sugar >= 0.9.2, < 0.10
pytest-benchmark >= 3.2.2, < 3.3
pytest-localserver >= 0.5.0, < 0.6
mock >= 3.0.0, < 4.1
Sphinx >= 1.8.0, < 2.4
WebTest >= 2.0.6, < 2.1
isort == 4.3.21