[Lower Priority] Implement "Fisher Induced Sparse uncHanging (FISH) Mask"

[haileyschoelkopf]

Paper: https://arxiv.org/pdf/2111.09839.pdf

Code: https://github.com/varunnair18/FISH/blob/main/transformers/examples/text-classification/run_glue_sparse_update.py

This will be relatively easy to add to our code.