It seems the deps folder is missing:
CMake Error at /opt/ros/melodic/share/catkin/cmake/catkin_package.cmake:305 (message):
catkin_package() include dir 'deps/pybind11/include' does not exist
relative to '/root/catkin_ws/src/SSMI/SSMI-Planning'
Call Stack (most recent call first):
/opt/ros/melodic/share/catkin/cmake/catkin_package.cmake:102 (_catkin_package)
SSMI/SSMI-Planning/CMakeLists.txt:18 (catkin_package)