Model checkpointing to just save the latest model
🚀 Feature
There is currently no automated option of always only keeping the latest saved model - there is always a metric benchmark used that needs to be exceeded. This is fine as a default but there should be a 'keep-it-simple' option of always just saving whatever is the latest.
Motivation
The concept of top-k is sound but when testing the capacity of new architectures, the most important is just to be resume the latest version. This can probably be implemented by using max(self.global_step) as the metric - but this seems overly complex.
Alternatives
An option to always save the latest model and no others - e.g. by setting save_top_k=-1 (instead of disabling saving altogether which is better done by not having a ModelCheckpoint).