Some mistakes in the code

[thuwyl]

Hi, When trying to run the code, I've got some errors.

• https://github.com/qcraftai/pillar-motion/blob/main/motion/datasets/nuscenes/flow.py in line 317. The type of saved data info['cam_coords'] is np.float32, directly load the data as np.int32 cause the "indexerror: list index out of range"
• https://github.com/qcraftai/pillar-motion/blob/main/motion/datasets/nuscenes/nusc_common.py in line 373. TypeError: unsupported operand type(s) for /: 'str' and 'str'
• https://github.com/qcraftai/pillar-motion/blob/main/motion/models/heads/chamfer.py in line 157. Here may be a spelling mistake.

Maybe you can check the code again. Thanks!