fix Using `low_cpu_mem_usage=True` or a `device_map` requires Accelerate: `pip install accelerate` error

requirements.txt

@@ -11,4 +11,5 @@ phonemizer>=3.0
 # espeak-ng>=1.51
 scipy>=1.11
 munch>=2.5
+accelerate>=1.2.0
 # git+https://github.com/hexgrad/Kokoro-82M