Update pyproject.toml to fix startup error

[AndreaGirlando]

Bug Description

When the application starts, it throws the following error:

cheshire_cat_core  |   File "/app/cat/looking_glass/cheshire_cat.py", line 145, in load_language_model
cheshire_cat_core  |     llm = FactoryClass.get_llm_from_config(selected_llm_config["value"])
cheshire_cat_core  |   File "/app/cat/factory/llm.py", line 35, in get_llm_from_config
cheshire_cat_core  |     return cls._pyclass.default(**config)
cheshire_cat_core  |   File "/usr/local/lib/python3.10/site-packages/langchain_core/load/serializable.py", line 113, in __init__
cheshire_cat_core  |     super().__init__(*args, **kwargs)
cheshire_cat_core  |   File "/usr/local/lib/python3.10/site-packages/pydantic/v1/main.py", line 341, in __init__
cheshire_cat_core  |     raise validation_error
cheshire_cat_core  | pydantic.v1.error_wrappers.ValidationError: 1 validation error for ChatOpenAI
cheshire_cat_core  | __root__
cheshire_cat_core  |   Client.__init__() got an unexpected keyword argument 'proxies' (type=type_error)

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Steps to Reproduce

1. Clone the repository.
2. Start the application using docker compose up.
3. Modify the embedding model settings.
4. Restart the application.
5. The error described above will appear during startup.

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Solution

The issue was caused by an unsupported proxies argument during the initialization process, likely due to a library compatibility problem.

The problem has been resolved by locking the httpx version to 0.27.2, as suggested in this issue discussion, ensuring the application starts without errors.

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Expected Behavior

The application should now start successfully, even after changing the embedding model settings.

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[pieroit]

Always a good idea to fix dependencies version. Thanks @AndreaGirlando

[pieroit]

P.S. next time PR on develop