Workaround for Python 2 on macOS
Workaround for Python 2 on macOS

ref: https://travis-ci.org/github/JuliaPy/pyjulia/jobs/678829870

(We should be removing Python 2 support. This is just a quick fix.)

JuliaPy/pyjulia,JuliaPy/pyjulia,JuliaLang/pyjulia