Are you building for the simulator? Or for a real device? If you’re building for the simulator, that won’t work, as discussed in the Xcode Release Notes:
The GameKit framework is missing from the SDK for the watchOS simulator. To work around this issue, develop for GameKit using a watchOS device which does include the framework. (27899791)
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Apple Developer Relations, Developer Technical Support, Core OS/Hardware
let myEmail = "eskimo" + "1" + "@apple.com"