update changelog

CHANGELOG.md

@@ -8,6 +8,14 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 # [unreleased]
 
+# [v5.0.0]
+
+## Changes
+
+- GPIO HAL: Renamed entries of enumerations to avoid nameclashes with Windows defines.
+  `IN` and `OUT` in `Direction` changed to `DIR_IN` and `DIR_OUT`.
+  `CALLBACK` in `GpioTypes` changed to `TYPE_CALLBACK`
+
 # [v4.0.0]
 
 ## Additions