🚀 Feature

Hi @vfdev-5 ,

I found that CheckpointHandler can't use the fixed filename to save latest model:
https://github.com/pytorch/ignite/blob/v0.4.2/ignite/handlers/checkpoint.py#L149
But this is a very important requirement on our side...How can I achieve that?
For example, I want to always save the best model as model.pt after validations during training.

Thanks.