MonthGridBackgroundView : initializer is inaccessible due to 'fileprivate' protection level #333
Description
When trying to implement calendar grid lines like in the README, I am unable to instantiate a MonthGridBackgroundView in a MonthGridBackgroundViewRepresentable for use with SwiftUI, due to the init being fileprivate. Along with the init being fileprivate, framesOfDays is also fileprivate as well.
Here is the section in the readme that mentions the month grid lines: https://github.com/airbnb/HorizonCalendar#adding-grid-lines
I assume the fileprivate access modifier was oversight?
