Update changelog

Author: sosthene-nitrokey

CHANGELOG.md

@@ -12,6 +12,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - Added `format` macro.
 - Added `String::from_utf16`.
 - Added `is_full`, `recent_index`, `oldest`, and `oldest_index` to `HistoryBuffer`
+- Added `VecView`, the `!Sized` version of `Vec`
 
 ### Changed