Add an ability to hide the date in the WheelDatePicker

[kasiopec]

I have another small requirement in my project to have an ability to hide date, and only have month year selector.

I have noticed you are hiding year if the range was null, so I made a small change following the same idea in my fork with the date case.

https://github.com/commandiron/WheelPickerCompose/commit/bfcd7f179466ad9ab83a3eceabe922b5aff3392b

Do you think it can be added?

[commandiron]

Hi @kasiopec of course can be added but actually I want to this feature more organized. Year and day should be hidden in the same way. I will review your code. Thanks for your support and your feature request.