I want to use the GameKit package for my Unity project. But how do I do that? Is the GameKit plugin already available from today? Where can I find it? I can only spot that at minute 02:02 from the video tutorial session Reach new players with Game Center dashboard, there is the Package Manager window from Unity with Apple.GameKit installed from com.apple.gamekit-1.0.0.tgz but I can't find the package with this name on the web.