factorio-space-age: name drv -space-age, rather than -experimental

  modDir = factorio-utils.mkModDirDrv mods mods-dat;

  base = with actual; {

    pname = "factorio-${releaseType}";

    # remap -expansion to -space-age to better match the attr name in nixpkgs.

    pname = "factorio-${if releaseType == "expansion" then "space-age" else releaseType}";

    inherit version src;

    preferLocalBuild = true;