Swtich to arm64 version of UnifyFileSytemApi.dynlib

Use version from
https://download.unity3d.com/download_unity/211490bb75a6/MacEditorInstallerArm64/Unity-6000.3.0b6.pkg

Previous commit 88c405f was using this download
https://download.unity3d.com/download_unity/211490bb75a6/MacEditorInstaller/Unity-6000.3.0b6.pkg

The file comes from this location inside the pkg:
Unity.pkg.tmp\Payload\Payload~\.\Unity\Unity.app\Contents\Frameworks\UnifyFileSytemApi.dynlib

Author: SkowronskiAndrew