How to use 'dynamic shape infer' in mlir 1.8?

[lizhengx]

Release Notes 1.8 writes: Added support for dynamic shape inference in various operations.
And i notice that two parameters are added to model_transform:
dynamic_inputs 否 指定动态输入名，例如 input1,input2
inputs_is_shape 否 shape 信息作为一个输入操作数

Can you give some examples? Thanks.