This actions setus up Godot in the Github Action runner

It downloads and caches the specified version of the headless Godot executable, and optionally the default export templates

!!! IT ONLY WORKS ON LINUX RUNNERS !!!

Any attempt to use this action on windows or macos will throw an error

steps:
  - uses: actions/checkout@v2
  - uses: vitorgus/setup-godot@v1
    with:
      godot-version: 3.3.3
  - name: Web Build
    run: |
      mkdir -v -p build/web
      godot -v --export "HTML5" ./build/web/index.html
  - uses: actions/upload-artifact@v2
    with:
      name: web
      path: build/web

Specifies the version for the Godot executable

If the version of godot to setup should be the mono version for C# projects. If false, will download the standard version.

Default Value: false

If the actions should also download Godot's default export templates

Default Value: true

Godot has a special headless executable made for automated CLI usage, and it's curently only available on linux.

I guess one could setup the normal godot version on windows and macOs runners if they really want to. But for now linux will be the only supported platform.