Quick add on .env_sample

NEO4J_URI=neo4j://localhost:7687...
NEO4J_USERNAME=neo4j...
NEO4J_PASSWORD=password...

{PR Message - Write freely, remove this bracket if unnecessary}

Author Checklist

• PR Title Format: I have confirmed that the PR title follows the correct format. (e.g., [N-2] 07-Text Splitter / 07-RecursiveCharacterTextSplitter)

• Committed Files: I have ensured that no unnecessary files (e.g., .bin, .gitignore, poetry.lock, pyproject.toml) are included. These files are not allowed.

• (Optional) Related Issue: If this PR is linked to an issue, I have referenced the issue number in the PR message. (e.g., Fixes Update 01-PromptTemplate.ipynb #123)

• ❌ Do not include unnecessary files (e.g., .bin, .gitignore, poetry.lock, pyproject.toml) or other people's code. If included, close the PR and create a new PR.

Review Template (Intial PR)

🖥️ OS: Win/Mac/Linux   
✅ Checklist      
 - [ ] **Template**: Tutorials follows the required template. 
 - [ ] **Table of Contents(TOC) Links**: All Table of Contents links work. ((Yes/No)
 - [ ] **Image**: Image filenames follow guidelines.
 - [ ] **Imports*: All import statements use the latest versions. Ensure "langchain-teddynote" is not used. 
 - [ ] **Code Execution**: Code runs without errors.
 - Comments: {Write freely, 한국어 기술 가능}     

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