Add Github Action for Build

[zalo]

I was working on integrating the exact same fix 😄

This should put a nice green checkmark on each commit... and it's the first step to publishing updated builds to npm automatically 😁

[zalo]

@fabmax (In-case you didn't see this one) Here's an example successful build: https://github.com/zalo/physx-js-webidl/actions/runs/7225519560

[fabmax]

Nice, thanks! It always takes me a while to set up github actions and therefore was too lazy doing so :smile: