Update README.md with new model card content

README.md

@@ -1,7 +1,7 @@
 ---
 library_name: keras-hub
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-### Model Overview
+## Model Overview
 # Stable Diffusion 3 Medium
 ![demo](https://huggingface.co/stabilityai/stable-diffusion-3-medium/resolve/main/sd3demo.jpg)
 
@@ -28,7 +28,7 @@ Please note: this model is released under the Stability Community License. For E
 ### Model card 
 https://huggingface.co/stabilityai/stable-diffusion-3-medium
 
-### Example Usage
+## Example Usage
 ```python
 # Pretrained Stable Diffusion 3 model.
 model = keras_hub.models.StableDiffusion3Backbone.from_preset(