EnCodec allows commercial use - new license

[ryanloney]

Can you update README and license now that Facebook Research updated their EnCodec model license to allow commercial use? It's now under MIT license. https://github.com/facebookresearch/encodec/commit/349b72939f57cb3bc7b60906c0ee8228c849485d

The README states that Suno models can be used for commercial purposes but EnCodec cannot.

Thank you!

-Ryan