Add python3 versions and pypy classifiers on setup.py
Add python3 versions and pypy classifiers on setup.py

It's a good practise to indicate them as they are showed on PyPi in
order to indicate which are the suported versions of the package.

daviddrysdale/python-phonenumbers,daviddrysdale/python-phonenumbers,daviddrysdale/python-phonenumbers,gencer/python-phonenumbers