Adds support for dark-mode and accessibility starting with iOS 13.

[cmriboldi]

Previous versions of iOS will work the same as before.

The color mapping that I used in the JZWeekViewColor is as follows.

UIColor.white --> systemBackground all used to color backgrounds
columnHeaderWeekday: UIColor { return UIColor(hex: 0x757575) } --> secondaryLabel
columnHeaderDay: UIColor { return UIColor(hex: 0x757575) } --> secondaryLabel
allDayHeader: UIColor { return UIColor(hex: 0x757575) } --> secondaryLabel
rowHeaderTime: UIColor { return UIColor(hex: 0x999999) } --> tertiaryLabel
gridLine: UIColor { return UIColor.lightGray } --> separator
today: UIColor { return UIColor(hex: 0x0089FF) } --> systemBlue
appleCalendarRed: UIColor { return UIColor(hex: 0xFC3D39) } --> systemRed

If you have any questions feel free to reach out. This is a fix that we're using at the company I'm working at in order to fully support dark mode and accessibility in our app. Hopefully, it's pretty straightforward.

I renamed a lot of the colors to be more semantic to match the new iOS UIColor naming conventions (with the exception of blue and red). There's a good article on that here. https://nshipster.com/dark-mode/

Thanks so much for your hard work on this pod!

[zjfjack]

@cmriboldi Thanks for the pr. It looks good to me.
Although JZWeekViewColors should be changed in the future, it is a fantastic solution now.
I am quite busy recently, I will try these colors first and merge it asap.

[eduardo3150]

@zjfjack, Hey ✋ when will this get merged?

[Stanley-Jovel]

The same here, wondering if this will get merged anytime soon.

[zjfjack]

I will try to restart some work recently. I stopped updating this project for a while. Hopefully next week.

…

On Wed, 19 Feb 2020 at 10:44, Eduardo Chavez ***@***.***> wrote: @zjfjack <https://github.com/zjfjack>, Hey ✋ when will this get merged? — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#109?email_source=notifications&email_token=ABEWYPRIGIEXOVM4XSEKZCDRDRXFJA5CNFSM4I5IRAD2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOEMFZEFI#issuecomment-587960853>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABEWYPXH2CEVYJL42IPXURLRDRXFJANCNFSM4I5IRADQ> .