message: watermask CHANGES.md
diff: ##### Additions :tada:
  +- Added water mask support (only quantized-mesh for now).
  - Improved property change checks in `Cesium3DTileset::LoadTileset`.
  - Added macOS support.
  - Added support for the legacy `gltfUpAxis` property in a tileset `asset` dictionary. Although this property is **not** part of the specification, there are many existing assets that use this property and had been shown with a wrong rotation otherwise.
  