add melotts to the requirements

requirements.txt

 nltk==3.8.1
 parler_tts @ git+https://github.com/huggingface/parler-tts.git
+melotts @ git+https://github.com/andimarafioti/MeloTTS.git  # made a copy of MeloTTS to have compatible versions of transformers
 torch==2.4.0
 sounddevice==0.5.0
 lightning-whisper-mlx==0.0.10