remove const ref for move to work

Author: saurabh1002

cpp/kiss_icp/pipeline/KissICP.cpp

@@ -35,7 +35,7 @@ namespace kiss_icp::pipeline {
 KissICP::Vector3dVectorTuple KissICP::RegisterFrame(const std::vector<Eigen::Vector3d> &frame,
                                                     const std::vector<double> &timestamps) {
     // Preprocess the input cloud
-    const auto &preprocessed_frame = preprocessor_.Preprocess(frame, timestamps, last_delta_);
+    Vector3dVector preprocessed_frame = preprocessor_.Preprocess(frame, timestamps, last_delta_);
 
     // Voxelize
     const auto &[source, frame_downsample] = Voxelize(preprocessed_frame);
@@ -69,8 +69,8 @@ KissICP::Vector3dVectorTuple KissICP::RegisterFrame(const std::vector<Eigen::Vec
 
 KissICP::Vector3dVectorTuple KissICP::Voxelize(const std::vector<Eigen::Vector3d> &frame) const {
     const auto voxel_size = config_.voxel_size;
-    const auto frame_downsample = kiss_icp::VoxelDownsample(frame, voxel_size * 0.5);
-    const auto source = kiss_icp::VoxelDownsample(frame_downsample, voxel_size * 1.5);
+    Vector3dVector frame_downsample = kiss_icp::VoxelDownsample(frame, voxel_size * 0.5);
+    Vector3dVector source = kiss_icp::VoxelDownsample(frame_downsample, voxel_size * 1.5);
     return {std::move(source), std::move(frame_downsample)};
 }
 void KissICP::Reset() {