FEAT: Upgrade langchain (0.3.x) and associated packages including langchain-astradb

[erichare]

This upgrades our langchain dependency to 0.3.x, adds ~= requirements to associated packages, and allows the use of the latest langchain-astradb as a result.

[edwinjosechittilappilly]

Did you encounter any issues with Pydantic when installing and running the backend of Langflow after the upgrade to 0.3.x? @erichare

[erichare]

Did you encounter any issues with Pydantic when installing and running the backend of Langflow after the upgrade to 0.3.x? @erichare

I admit i haven't extensively tested it, would love some help from others, but i was able to build and start the backend service without problems. I was also able to run my existing flows i had saved. I do see deprecation warnings about pydantic:

Starting Langflow v1.0.19...
/Users/erichare/GitHub/langflow/src/backend/base/langflow/utils/validate.py:224: LangChainDeprecationWarning: As of langchain-core 0.3.0, LangChain uses pydantic v2 internally. The langchain.pydantic_v1 module was a compatibility shim for pydantic v1, and should no longer be used. Please update the code to import from Pydantic directly.

But it doesn't appear to block the startup. question is whether we would like to go through and remove references to pydantic_v1, or defer that for later?

[edwinjosechittilappilly]

Did you encounter any issues with Pydantic when installing and running the backend of Langflow after the upgrade to 0.3.x? @erichare

I admit i haven't extensively tested it, would love some help from others, but i was able to build and start the backend service without problems. I was also able to run my existing flows i had saved. I do see deprecation warnings about pydantic:

Starting Langflow v1.0.19...
/Users/erichare/GitHub/langflow/src/backend/base/langflow/utils/validate.py:224: LangChainDeprecationWarning: As of langchain-core 0.3.0, LangChain uses pydantic v2 internally. The langchain.pydantic_v1 module was a compatibility shim for pydantic v1, and should no longer be used. Please update the code to import from Pydantic directly.

But it doesn't appear to block the startup. question is whether we would like to go through and remove references to pydantic_v1, or defer that for later?

Thats cool. Earlier when I tried the upgrade I faced some Pydantic upgrade error.
Let me review it and shall let you know soon.

[edwinjosechittilappilly]

Tested. Looks good to me.
The SecretStr error I observed earlier seems to be managed. Perhaps, as a follow-up pull request, we can add a chore to upgrade Pydantic from version 2.0 to 3.0 in some functionalities.

[edwinjosechittilappilly]

@erichare can you resolve the conflicts in uv.lock?

[edwinjosechittilappilly]

LGTM