See Document for more detail.

Add it to your editor's manifest.json file like this:

{
    "dependencies": {
        "com.macacagames.utility": "https://github.com/MacacaGames/MacacaUtility.git#1.0.0",
    }
}

You can remove the #1.0.0 to use the latest version (unstable)

Note: GameSystem is dependency with Rayark.Mast, so also add it in git submodule.

git submodule add https://github.com/MacacaGames/MacacaUtility.git Assets/MacacaUtility