Bump version to 2.0.0 (#288)

HorizonCalendar.podspec

@@ -1,6 +1,6 @@
 Pod::Spec.new do |spec|
   spec.name = "HorizonCalendar"
-  spec.version = "1.16.0"
+  spec.version = "2.0.0"
   spec.license = "Apache License, Version 2.0"
   spec.summary = "A declarative, performant, calendar UI component that supports use cases ranging from simple date pickers to fully-featured calendar apps."
 
@@ -11,15 +11,18 @@ Features:
 
 - Supports all calendars from `Foundation.Calendar` (Gregorian, Japanese, Hebrew, etc.)
 - Display months in a vertically-scrolling or horizontally-scrolling layout
-- Declarative API that enables unidirectional data flow for updating the content of the calendar
+- Declarative API that encourages unidirectional data flow for updating the content of the calendar
 - A custom layout system that enables virtually infinite date ranges without increasing memory usage
+- Animated content updates
 - Pagination for horizontally-scrolling calendars
+- Self-sizing month headers
 - Specify custom views (`UIView` or SwiftUI `View`) for individual days, month headers, and days of the week
 - Specify custom views (`UIView` or SwiftUI `View`) to highlight date ranges
 - Specify custom views (`UIView` or SwiftUI `View`) to overlay parts of the calendar, enabling features like tooltips
 - Specify custom views (`UIView` or SwiftUI `View`) for month background decorations (colors, grids, etc.)
 - Specify custom views (`UIView` or SwiftUI `View`) for day background decorations (colors, patterns, etc.)
 - A day selection handler to monitor when a day is tapped
+- A multi-day selection handler to monitor when multiple days are selected via a drag gesture
 - Customizable layout metrics
 - Pin the days-of-the-week row to the top
 - Show partial boundary months (exactly 2020-03-14 to 2020-04-20, for example)