Update httplib2 to 0.17.3#462

pyup-bot wants to merge 1 commit intomastercclauss/pythonista-module-versions:masterfrom

pyup-update-httplib2-0.9.2-to-0.17.3cclauss/pythonista-module-versions:pyup-update-httplib2-0.9.2-to-0.17.3Copy head branch name to clipboard