Critical Normalization error in DeiT_example.ipynb

Hi,

The normalization used in the Deit_example.ipynb is incorrect. It should actually be: `normalize = transforms.Normalize(mean=[0.485, 0.456, 0.406], std=[0.229, 0.224, 0.225])`

I checked the results, and they seem to be dramtically better in terms of accuracy. 

Maybe this was on accident and should be fixed.

Thanks!
