Add accelerate to requirements

Add accelerate to requirements to fix the following error:

```
ImportError: Using `load_in_8bit=True` requires Accelerate: `pip install accelerate` and the latest version of bitsandbytes `pip install -i https://test.pypi.org/simple/ bitsandbytes` or pip install bitsandbytes`
```

requirements.txt

@@ -1,6 +1,7 @@
 torch
 gradio
 transformers
+accelerate
 bitsandbytes
 loralib
 scipy