Security fix: update pydantic to >=2.4.0 to address CVE-2024-3772

- Addresses MEDIUM severity vulnerability found in pydantic <2.4.0
- Fixed per Codacy/Trivy analysis recommendation

Author: vinod0m

requirements.txt

@@ -2,7 +2,7 @@ langchain==0.3.27
 langchain-google-genai==2.1.9
 langchain-community==0.3.27
 langchain-ollama==0.3.6
-pydantic>=2.0.0
+pydantic>=2.4.0
 fastapi==0.117.1
 uvicorn==0.37.0
 psycopg2-binary==2.9.10