ImageNet-21k -> 1k fine-tunes

[rwightman]

@lyttonhao do you happen to have the links to the fine-tuned 1k weights mentioned in the paper @ 224x224, 384x384 and 512x512 for the L/H models?

They're pretty decent results but aside from that they were of interest as they are some of the few weights fine-tuned weights I'm aware of pretrained on the winter21 variant of 21k.