Use case

Unless it's there and I've totally missed it, I would like a way to customize the shape of the year items in the date picker.

Proposal

There is currently a dayShape property in the DatePickerThemeData, allowing me to customize the shape of the day items; there could/should be an analogous property for the year items.

I can change the shape of the day items to match my app's style:

But the years only have the standard circular radius: