Bump to v1.15.4.

Author: kring

CHANGES.md

@@ -1,5 +1,13 @@
 # Change Log
 
+## v1.15.4 - 2025-03-03
+
+##### Fixes :wrench:
+
+- "External Tilesets" are now unloaded when they are no longer used. This will significantly reduce the growth of memory usage over time when using Google Photorealistic 3D Tiles and similar tilesets.
+
+This release updates [cesium-native](https://github.com/CesiumGS/cesium-native) from v0.44.3 to v0.45.0. See the [changelog](https://github.com/CesiumGS/cesium-native/blob/main/CHANGES.md) for a complete list of changes in cesium-native.
+
 ## v1.15.3 - 2025-02-12
 
 This release updates [cesium-native](https://github.com/CesiumGS/cesium-native) from v0.44.2 to v0.44.3. See the [changelog](https://github.com/CesiumGS/cesium-native/blob/main/CHANGES.md) for a complete list of changes in cesium-native.

native~/extern/cesium-native

@@ -1,6 +1,6 @@
 {
   "name": "com.cesium.unity",
-  "version": "1.15.3",
+  "version": "1.15.4",
   "displayName": "Cesium for Unity",
   "description": "Cesium for Unity brings the 3D geospatial ecosystem to Unity. By combining a high-accuracy full-scale WGS84 globe, open APIs and open standards for spatial indexing such as 3D Tiles, and cloud-based real-world content from [Cesium ion](https://cesium.com/cesium-ion) with Unity, this plugin enables 3D geospatial workflows and applications in Unity.",
   "license": "Apache-2.0",