Lm-format-enforcer

- Bug fixes

- vLLM performance improvements
- Sample notebooks don't require huggingface account anymore

- Added [ExLlamaV2 integration](https://github.com/noamgat/lm-format-enforcer/blob/main/samples/colab_exllamav2_integration.ipynb)

- JSON Schema: Added support for union types. In pydantic, both `key: int | str` and `key: Union[int, str]` formats are supported
- JSON Schema: Added support for schemaless JSON mode. `JsonSchemaParser(None)` will now create a parser that accepts any valid JSON.

- Added official vLLM integration that doesn't require monkey patching.

- JSON Schema : Supports string min/max length limitation