Update cryptography to 2.3.1#52

pyup-bot wants to merge 1 commit intomastermwisner/python-cimpress:masterfrom

pyup-update-cryptography-2.0.3-to-2.3.1mwisner/python-cimpress:pyup-update-cryptography-2.0.3-to-2.3.1Copy head branch name to clipboard