CI / GitHu bactions: Production built windows/linux

[Lecrapouille]

From Godot editor Sconstruct:

    if env["production"]:
        if not env["tools"] and env["target"] == "debug":
            print(
                "WARNING: Requested `production` build with `tools=no target=debug`, "
                "this will give you a full debug template (use `target=release_debug` "
                "for an optimized template with debug features)."
            )
        if env.msvc:
            print(
                "WARNING: For `production` Windows builds, you should use MinGW with GCC "
                "or Clang instead of Visual Studio, as they can better optimize the "
                "GDScript VM in a very significant way. MSVC LTO also doesn't work "
                "reliably for our use case."
                "If you want to use MSVC nevertheless for production builds, set "
                "`debug_symbols=no use_lto=no` instead of the `production=yes` option."
            )

[Lecrapouille]

With github action we do not compile using production and for windows that would mean to use https://github.com/marketplace/actions/install-mingw