Automatic builds via GitHub Actions

[BuyMyMojo]

Would be pretty cool to get the latest files through github's action system

[bozbez]

This would require a little more consideration that the most simple CMake example as we might need to build OBS (or fetch the built libobs from somewhere), and also compile both the 64 bit and 32 bit versions of the hook and helper.

Certainly possible, but not high priority for 1.0.0 since I will be packaging the releases fairly frequently anyway.

[bozbez]

One of these might be a good starting point:

• https://github.com/justusdieckmann/obs_win-processaudio/blob/main/.github/workflows/package.yml
• https://github.com/exeldro/obs-move-transition/blob/master/.github/workflows/build.yml

Note that this plugin builds out-of-tree so we will need to build the plugin in a separate directory after building OBS.