Pixart model weight support

[311-code]

The model weights for a new model called pixart-a have released. SD.next just added it but I can't figure out of to get it working even with his changelog instructions. Would love to see this added to auto1111 https://huggingface.co/PixArt-alpha/PixArt-XL-2-1024-MS/tree/main

[maxi1134]

Have you found how to use this?