Example for Customized Audio Classifier

[neugartf]

Hey!

I tried to retrain the audio classifier until I noticed that the mentioned classes in https://colab.research.google.com/github/googlesamples/mediapipe/blob/main/examples/customization/image_classifier.ipynb (I used this as a guideline) didn't exist for the audio classifier. Would be great to have this for the audio classification too.

Thanks :)