Update changelog

Author: GrantM11235

CHANGELOG.md

@@ -11,10 +11,13 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - New `DisplayError` variant `RSError` to use with problems with the display's reset signal
 - New `DisplayError` variant `OutOfBoundsError` to use when writing to a non-existing pixel outside the display's bounds
+- parallel-gpio: New `OutputBus` trait
+- parallel-gpio: Added `Generic8BitBus`, an implementation of `OutputBus`
 
 ### Changed
 
 - Return `DCError` instead of `BusWriteError` on errors (de-)asserting the DC signal in 8-bit GPIO interfaces
+- **Breaking** parallel-gpio: `PGPIO8BitInterface` now uses any 8-bit impementation of `OutputBus` instead of 8 individual pins
 
 ## [v0.4.0] - 2020-05-25