Support for PyTorch 1.6.0

[guhur]

Hi,
Thanks for sharing your code!
I run the tests with PyTorch 1.6.0 and quite a lot of them are failing. It might be because PyTorch changed from version 1.1.0 on how they manage the bool tensors.

It would be nice if you have time to update your code so newest version of PyTorch

Best,
Pierre

[vene]

This would be a very welcome contribution if you have the time!

For sparsemax and entmax please also consider the deep-spin/entmax package