add_exllamav2 (#1419)
* add_exllamav2
* style
* fix doc
* fix doc
* raise error
* Update docs/source/llm_quantization/usage_guides/quantization.mdx
Co-authored-by: fxmarty <9808326+fxmarty@users.noreply.github.com>
* update doc
* update min version of autogptq
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Co-authored-by: fxmarty <9808326+fxmarty@users.noreply.github.com>
