The compatibility for the later version pytorch

[GongXinyuu]

In the original implementation, an error will occur "RuntimeError: A view was created in no_grad mode and is being modified inplace with grad mode enabled" using PyTorch 1.8.

[eric8607242]

Thanks for the pull request!
To make sure the gradient flow and update the architecture generator, I think that the architecture parameter may not be detached in line 222 of lookup_table_builder.py.