Bump langchain from 0.2.1 to 0.2.14

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.2.1 to 0.2.14.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==0.2.1...langchain==0.2.14)

---
updated-dependencies:
- dependency-name: langchain
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

requirements.txt

@@ -1,7 +1,7 @@
 faiss-cpu==1.8.0
 duckduckgo_search==6.1.7
 beautifulsoup4==4.12.3
-langchain==0.2.1
+langchain==0.2.14
 langchain-community==0.2.1
 unstructured==0.14.2
 rank_bm25==0.2.2