[Core] Update to outlines >= 0.1.8

0.1.x prior to 0.1.8 + outlines-core 0.1.18 had issues with
serialization that broke vllm integration.

Also change our code slightly to account for an API change in
outlines.

Signed-off-by: Russell Bryant <rbryant@redhat.com>

requirements-common.txt

@@ -18,7 +18,7 @@ prometheus_client >= 0.18.0
 prometheus-fastapi-instrumentator >= 7.0.0
 tiktoken >= 0.6.0  # Required for DBRX tokenizer
 lm-format-enforcer >= 0.10.9, < 0.11
-outlines >= 0.0.43, < 0.1
+outlines >= 0.1.8
 xgrammar >= 0.1.6; platform_machine == "x86_64"
 typing_extensions >= 4.10
 filelock >= 3.16.1 # need to contain https://github.com/tox-dev/filelock/pull/317

vllm/model_executor/guided_decoding/outlines_logits_processors.py

@@ -99,7 +99,7 @@ class RegexLogitsProcessor(BaseLogitsProcessor):
     def _get_guide(cls, regex_string: str,
                    tokenizer: PreTrainedTokenizerBase) -> Guide:
         tokenizer = _adapt_tokenizer(tokenizer)
-        return RegexGuide(regex_string, tokenizer)
+        return RegexGuide.from_regex(regex_string, tokenizer)
 
     def __init__(self, regex_string: str, tokenizer: PreTrainedTokenizerBase):
         """Compile the FSM that drives the regex-structured generation.