Ability to run validation on last epoch, even when using `check_val_every_n_epoch`
🚀 Feature
The ability to run a validation loop after the very last training epoch, even when check_val_every_n_epoch > 1 and the last epoch doesn't coincide with current_epoch % check_val_every_n_epoch == 0.
Motivation
Sometimes it's nice to run validation less often, for instance to speed up training, but I usually want to see the final validation accuracy even if I've skipped it on some of the intermediate epochs.
Pitch
I'm not sure what the best way to implement this feature is; perhaps another flag in Trainer, although there are already quite a few there.
cc @Borda @tchaton @justusschock @awaelchli @carmocca @ananthsub @ninginthecloud @rohitgr7