I have not tried this, so I don't know if it would work, but if you put the 'future' package in the right place inside the application, it seems like it should work, since Chirp is unsigned. That is, copy the 'future' package you just installed from your global Python site-packages directory to:
[wherever-you-put-the-chirp-application]/CHIRP.app/Contents/Resources/site-packages/
Again, I haven't tried it, but if you're willing to fiddle around a bit, you could try it and see what happens.
Martin.
KD6YAM