The model_name: altdiffusion-m18 is not be supported

[xuhzyy]

System Info

flagai=1.6.2 python=3.8

Information

• [X] The official example scripts
• [ ] My own modified scripts

Tasks

• [X] An officially supported task in the examples folder (such as T5/AltCLIP, ...)
• [ ] My own task or dataset (give details below)

Reproduction

to generate image using altdiffusion-m18: python generate.py

Expected behavior

generate image from the text