[Feature] find the proper learning rate

[bowenroom]

What is the feature?

Pick the proper starting learning rate is crucial for the experiment. I think the lr_finder in fastai is very useful. Could you add this function into mmengine? We will thanks for all the hard work. The usage of this function can be found at https://fastai1.fast.ai/callbacks.lr_finder.html#Learning-Rate-Finder

Any other context?

No response

[zhouzaida]

Hi @bowenroom , thanks for your feature request. This is a useful feature and we will add it to #916.