Remove AMP

[mueller91]

Describe the bug

Hi everybody,

Trainer is great, but still uses APEX, which is deprecated and tends to cause problems.
Could you remove and/or replace with Nvidia/amp?

Best regrads

To Reproduce

Just run Trainer on an Nvidia GPU

Expected behavior

No response

Logs

No response

Environment

not relevant

Additional context

No response

[erogol]

But looks like all is put into torch natively, so yes there is no point keep it.