update external headers

ios/include/filament/Engine.h

@@ -35,9 +35,11 @@ class ColorGrading;
 class DebugRegistry;
 class Fence;
 class IndexBuffer;
+class SkinningBuffer;
 class IndirectLight;
 class Material;
 class MaterialInstance;
+class MorphTargetBuffer;
 class Renderer;
 class RenderTarget;
 class Scene;
@@ -419,6 +421,8 @@ public:
     bool destroy(const VertexBuffer* p);        //!< Destroys an VertexBuffer object.
     bool destroy(const Fence* p);               //!< Destroys a Fence object.
     bool destroy(const IndexBuffer* p);         //!< Destroys an IndexBuffer object.
+    bool destroy(const SkinningBuffer* p);      //!< Destroys a SkinningBuffer object.
+    bool destroy(const MorphTargetBuffer* p);   //!< Destroys a MorphTargetBuffer object.
     bool destroy(const IndirectLight* p);       //!< Destroys an IndirectLight object.
 
     /**