fix: missing declare

Signed-off-by: badai-nguyen <dai.nguyen@tier4.jp>

Author: badai-nguyen

perception/autoware_image_projection_based_fusion/include/autoware/image_projection_based_fusion/roi_pointcloud_fusion/node.hpp

@@ -46,6 +46,7 @@ class RoiPointCloudFusionNode : public FusionNode<PointCloudMsgType, RoiMsgType,
   int max_cluster_size_{20};
   bool fuse_unknown_only_{true};
   double cluster_2d_tolerance_;
+  double roi_scale_factor_{1.0};
 
   std::vector<ClusterObjType> output_fused_objects_;
 };