Microsoft.UI.Xaml v2.2.190830001

This is the official release of the WinUI 2.2 package!

https://www.nuget.org/packages/Microsoft.UI.Xaml/2.2.190830001

Release notes: https://docs.microsoft.com/en-us/uwp/toolkits/winui/release-notes/winui-2.2

Notable bug fixes since last prerelease:

• Added RevealStyle for DropDownButton and SplitButton; Closes #70; (ddbc3368 by chingucoding, pr #1211)
• TabView handles unconstrained layouts (891bfdbd by kmahone, pr #1220)
• Fix ItemsSource and TreeViewNode syncing (165fc3cb by kaiguo, pr #1202)
• Add 1px Separator in SplitButton (9ce92ff0 by savatia, pr #1173)
• NavigationView: Fixing visibility of close button in Auto PaneDisplayMode and Minimal DisplayMode (27d6b33e by RBrid, pr #1195)