the generated macos app iconset is invalid

[andy380743909]

my Fastfile

lane :gen_appicon do
    appicon(
      appicon_image_file: 'iBackupExplorer/Resources/AppIcon512.png',
      appicon_devices: [:macos],
      appicon_path: 'iBackupExplorer/Resources/Assets.xcassets'
    )
  end

the generated appiconset

I guess this is caused by the wrong param appicon_devices value [:macos], the right value should be [:mac].
If I changed the generated appiconset's Content.json, it turns to valid.

see #15