Run the test.py about Human36M dataset

[Zhiying-Li-dot]

When I run the test.py, dataset is set Human36M. It report exceptions "Traceback (most recent call last):
File ```
"test.py", line 99, in
main()
File "test.py", line 88, in main
cur_eval_result = tester._evaluate(out, cur_sample_idx)
File "/data/zhiyingli/SMPLer-X/main/../common/base.py", line 309, in _evaluate
eval_result = self.testset.evaluate(outs, cur_sample_idx)
File "/data/zhiyingli/SMPLer-X/main/../data/Human36M/Human36M.py", line 256, in evaluate
mesh_out = out['smpl_mesh_cam'] * 1000 # meter to milimeter
KeyError: 'smpl_mesh_cam'"