CHANGELOG update

Author: korken89

CHANGELOG.md

@@ -13,7 +13,8 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 - [breaking-change] `HistoryBuffer` is now working with const constructors and non-`Copy` data
 - [breaking-change] `HistoryBuffer::as_slice` and others now only return initialized values
 - [breaking-change] `MultiCore`/`SingleCore` is now removed from `spsc::Queue`
-- [breaking-change] `spsc::Queue::u8()` and `spsc::Queue::u16()` are now unsafe
+- [breaking-change] `spsc::Queue` is now `usize` only
+- [breaking-change] `spsc::Queue` now sacrifices one element for correctness (see issue #207)
 - `Pool` and `MPMC` now works on `thumbv6m`
 - [breaking-change] `String` has had `utf8` related methods removed as this can be done via `str`
 - [breaking-change] No data structures implement `AsSlice` traits any more, now using `AsRef` and `AsMut`