PyOpenSSL now specifies 3.x classifiers
PyOpenSSL now specifies 3.x classifiers

Pull request submitted to get Python 3 classifier added
brettcannon/caniusepython3,svisser/caniusepython3,nett55/caniusepypy,public/caniusepypy,ctismer/caniusepython3,dhamaniasad/caniusepython3