Cross-platform CI pipeline

[kmturley]

Fixes #12

Automatically builds artifacts for Linux, Mac and Windows.

See a previous run on my repo here:
https://github.com/kmturley/aeolus_plugin/actions/runs/3140817066

There is currently an error with the Windows build:

D:/a/aeolus_plugin/aeolus_plugin/Source/aeolus/simd.cpp:45:5: error: '__cpuid' was not declared in this scope
   45 |     __cpuid((int*) regs, (int) funcId);
      |     ^~~~~~~

I believe this is a coding issue rather than a CI configuration issue?

[Archie3d]

This is great, thanks!
The error you are getting is because of mingw/gcc, which I have never supported. You can try to fix it including intrin.h in simd.cpp. Or rather use MSVC compiler (JUCE has rather poor support for mingw from my experience).

[kmturley]

Good suggestion!
It is building artifacts now, I haven't validated the artifacts work though...
https://github.com/kmturley/aeolus_plugin/actions/runs/3148410878

[Archie3d]

Excellent, the artefacts seem to be working correctly. I would tweak the upload though (so that it ignores the intermediary libs).