use compatible GTSAM version 4.0.2

README.md

@@ -63,9 +63,12 @@ This is the original ROS1 implementation of LIO-SAM. For a ROS2 implementation s
   ```
 - [gtsam](https://gtsam.org/get_started/) (Georgia Tech Smoothing and Mapping library)
   ```
-  sudo add-apt-repository ppa:borglab/gtsam-release-4.0
-  sudo apt update
-  sudo apt install libgtsam-dev libgtsam-unstable-dev
+  wget -O ~/Downloads/gtsam.zip https://github.com/borglab/gtsam/archive/4.0.2.zip
+  cd ~/Downloads/ && unzip gtsam.zip -d ~/Downloads/
+  cd ~/Downloads/gtsam-4.0.2/
+  mkdir build && cd build
+  cmake -DGTSAM_BUILD_WITH_MARCH_NATIVE=OFF ..
+  sudo make install -j8
   ```
 
 ## Install