Could The api note python version,and add requirements.txt?

[DavideHe]

In api/data/export_kitti_depth_benchmark.py some syntax do not support in python3.6 and numpy should update 1.21.x ,but python3.6 not support this

mybe there are other error by lib version or pytho version,so if ok , add information of python version and requirements.txt.

[jspenmar]

I have now added this information to the README. Please note that exact versions of each library (including Python) are already shown in environment.yml.