lightning_base: new clarg: lr_scheduler=polynomial_decay
lr_scheduler should be a string with many options, including polynomial_decay, like this [command](https://github.com/pytorch/fairseq/blob/master/examples/mbart/README.md#finetune-on-en-ro)
@stas00 as discussed on slack<|||||>got it<|||||>PR for stage 1 to support the existing schedulers: https://github.com/huggingface/transformers/pull/6232
once this is happy and merged, I will work on importing new ones.<|||||>poly: https://github.com/huggingface/transformers/pull/6361<|||||>@sshleifer, so now that get_polynomial_decay_schedule_with_warmup is done (about to be merged) - do we need any others?<|||||>Not that I know of. We can close this once the associated PR  ismerged.