Add changelog note

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 929517b..44bf57f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
+### Added
+- Enable still picture mode with rav1e >= 0.3.0 (cryptomilk)
 
 ## [0.5.4] - 2020-01-21
 ### Changed