Customise corner radius for day selection

[gerchicov-vg]

New Issue Checklist

• Use the latest version of CalendarKit
• I've read the Contribution Guidelines
• I've searched for existing GitHub issues

Issue Description

In my particular case I need to make a corner radius smaller. And currently it requires to edit inner library code.

Code I'm using with CalendarKit

Result I am trying to achieve

As I understand this corner radius is set here:
https://github.com/richardtop/CalendarKit/blob/master/Sources/Header/DaySelector/DateLabel.swift

    override public func layoutSubviews() {
        layer.cornerRadius = bounds.height / 2
    }

there is also an option private var style = DaySelectorStyle() which could contain an info about corner radius.

[richardtop]

Could you please adjust the library so that it's possible to customize with the style and submit a pr?