Feature request: automatically use correct case for dialog actions

[amugofjava]

Action labels on iOS use sentence case whereas on Material Design they are all upper case. It would be really useful to be able to supply Flutter Dialogs with a sentence case String which can be used directly on iOS, but automatically set to upper case when on Android.

A good example can be found on the Material Design Guidelines site if you scroll down to Cross Platform Adaptations.

Thank you.

[joshuadeguzman]

Would you prefer having a find grained control of the child text instead?