version bump v4.0.3

Author: RealMuffinTime

CHANGELOG.md

@@ -1,3 +1,8 @@
+## Version [v4.0.3](https://github.com/RealMuffinTime/muffintime-resource-pack/releases/tag/v4.0.3) - 2025-06-01
+### Changes
+- Move to new custom_model_data format
+- Support Minecraft version `1.21.4`
+
 ## Version [v4.0.2](https://github.com/RealMuffinTime/muffintime-resource-pack/releases/tag/v4.0.2) - 2025-06-01
 ### New stuff
 - Added spacex falcon as firework rocket texture