GFSocialType is missing `apple`

[lukehutch]

Is your feature request related to a problem? Please describe.

Apple now requires that if you support any OAuth social login system on an app in the iTunes store, you have to also support AppleID login.

GetWidget does not have a GFSocialType.apple button type for GFSocialButton.

Describe the solution you'd like

AppleID login needs to be supported.

Describe alternatives you've considered

I want to use a custom FontAwesome icon for this, but GFSocialButton only supports a limited set of button types, and I don't see a way to make a custom icon type.

Additional context

The rules are quoted here:

https://developer.apple.com/forums/thread/124006

[lukehutch]

See the supported button types for this social login button library:

https://pub.dev/packages/social_login_buttons

[atul-vashisht]

Thank you @lukehutch for updating about this , our team will look into this.