update to Filament libs with inverse bind matrices

ios/include/gltfio/FilamentInstance.h

@@ -126,7 +126,12 @@ public:
      */
     void detachSkin(size_t skinIndex, utils::Entity target) noexcept;
 
-    const math::mat4f* getInverseBindMatricesAt(size_t skinIndex) const noexcept;
+    /**
+     * Gets inverse bind matrices for all joints at the given skin index.
+     *
+     * See getJointCountAt for determining the number of matrices returned (i.e. the number of joints).
+     */
+    math::mat4f const* getInverseBindMatricesAt(size_t skinIndex) const;
 
     /**
      * Resets the AABB on all renderables by manually computing the bounding box.