fix: readme

Author: flavioschneider

README.md

@@ -130,7 +130,7 @@ mel_spectrogram = torch.randn(1, 2, 80, 1024) # [batch, in_channels, mel_channel
 sample = vocoder.sample(mel_spectrogram, num_steps=10) # Output has shape: [1, 2, 2**18]
 ```
 
-## Diffusion Autoencoder
+### Diffusion Autoencoder
 Autoencode audio into a compressed latent using diffusion. Any encoder can be provided as long as it subclasses the `EncoderBase` class or contains an `out_channels` and `downsample_factor` field.
 ```py
 from audio_diffusion_pytorch import DiffusionAE, UNetV0, VDiffusion, VSampler