Update README.md

[jackpeters667]

Hi there. I'm following the readme and the link it takes me to to download the models does not have the files that the readme asks me to download. I realise it's a link to an external repo but could we maybe provide the version that the readme was compiled against at the very least, or something? The models now use .pbmm extensions and .tflite ones. I have no idea which one I'm supposed to use now so it's just a trial and error thing.