Fix incorrect date in changelog

CHANGELOG.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2c2a9bc..9baf838 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,7 +6,7 @@
 
 ## [Unreleased]
 
-## [0.1.2] - 2019-04-15
+## [0.1.2] - 2019-04-18
 ### Added
 - `AVIF_NCLX_COLOUR_PRIMARIES_P3` (convenient mirrored value)
 - `avifNclxColourPrimariesFind()` - Finds a builtin avifNclxColourPrimaries and name by a set of primaries