Update CHANGELOG.md

Author: onurkerimov

CHANGELOG.md

@@ -12,7 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 <Calendar
   dateDisplayFormat='MMM D, YYYY'
   monthDisplayFormat='MMM YYYY'
-  weekdayDisplayFormat='E'
+  weekdayDisplayFormat='ddd'
   dayDisplayFormat='D'
 />
 ```
@@ -169,4 +169,4 @@ Momentjs: `moment(dateString).toDate()`
 - `initialFocusedRange` prop added: Initial value for focused range. See `focusedRange` for usage.
 - `onRangeFocusChange` prop added: Callback function for focus changes by user.
 - `dragSelectionEnabled` prop added
-- `showMonthAndYearPickers` prop added
+- `showMonthAndYearPickers` prop added