Update installation instructions

Author: dmronga

installation/installation_ros2.md

@@ -13,7 +13,9 @@
    git clone https://github.com/ARC-OPT/wbc_msgs.git
    git clone https://github.com/ARC-OPT/wbc_ros.git
    cd ..
-   rosdep install --from-paths src/wbc_msgs
+   rosdep install --from-paths src/wbc_ros
+   colcon build --packages-select wbc_msgs
+   source install/setup.bash
    colcon build
    source install/setup.bash
    ```