Update setup.py to download pyannote depending on platform

[justinwlin]

#540

Breaks Mac platform and arm64 platforms.

Tested by successfully building on my m1 mac doing:
pip install .

And also using Depot (a way to build Dockerfiles remotely, using arm64):
depot build -t whisperx_image . --platform linux/arm64 --load

[m-bain]

thank you, yes sorry about the mac issues. I had originally been designing this for desktop / commerical gpus usage, not PC, since thats quite common in my research area. But seems a lot of people are using whisperx on mac