fix: update 00-langchain-intro (#450)

fix: Updated
learn\generation\langchain\handbook\00-langchain-intro.ipynb to Work
with LangChain 0.3

Used newer models and new HuggingFaceEndpoint() class (instead of the,
now deprecated, HuggingFaceHub() class.

## Problem

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why?

## Solution

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or other resources.

## Type of Change

- [ ] Bug fix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] This change requires a documentation update
- [ ] Infrastructure change (CI configs, etc)
- [ ] Non-code change (docs, etc)
- [ ] None of the above: (explain here)

## Test Plan

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Co-authored-by: James Briggs <[email protected]>

Author: Siraj-Aizlewood