PatchMerging padding error

[wyli]

Describe the bug

import torch

from monai.networks.nets.swin_unetr import PatchMerging

dim=10
t = PatchMerging(dim)(torch.zeros((1, 21, 20, 20, dim)))
print(t.shape)

Traceback (most recent call last):
  File "my_test_3.py", line 7, in <module>
    t = PatchMerging(dim)(torch.zeros((1, 21, 20, 20, dim)))
  File "py38/lib/python3.8/site-packages/torch/nn/modules/module.py", line 1130, in _call_impl
    return forward_call(*input, **kwargs)
  File "MONAI/monai/networks/nets/swin_unetr.py", line 701, in forward
    x = torch.cat([x0, x1, x2, x3, x4, x5, x6, x7], -1)
RuntimeError: Sizes of tensors must match except in dimension 4. Expected size 11 but got size 10 for tensor number 1 in the list.