Adding new SOTA backbones

[hnuzhy]

Thank you for your perfect work! Recently, I'm working on a project using this lib for importing different backbones. But I found that the latest models are those released in year 2020. Are you planning to add new SOTA backbones into this lib? Such as ViT, Swin-Transformer, EfficientNet-V2, ViT-22B, or EfficientNet-ViT.