Problem with pybind11

Hello,
I have just updated the bgslibrary, which is very useful for my research by the way so very greatful for sharing it with us, to the pybind for binding with python. However when I try to run cmake to build Python support I get the two following errors.
First it tells me that there are no CmakeLists.txt files for pybind11
CMake Error at CMakeLists.txt:120 (add_subdirectory):
The source directory

/Users/Ozgun/Documents/VideoSurveillance/bgslibrary-master/git/bgslibrary/pybind11

does not contain a CMakeLists.txt file.

and then as expected

CMake Error at CMakeLists.txt:189 (pybind11_add_module):
Unknown CMake command "pybind11_add_module".

I am running cmake version 3.10.1 on a MacOs. I have no problem with the usual build only when I need to build the python bindings.
Thank you