Bump langchain from 0.1.9 to 0.3.0 in /applications/rag/frontend/cont…

…ainer (GoogleCloudPlatform#867)

Bump langchain in /applications/rag/frontend/container

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.1.9 to 0.3.0.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-ibm==0.1.9...langchain==0.3.0)

---
updated-dependencies:
- dependency-name: langchain
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

applications/rag/frontend/container/requirements.txt

@@ -15,7 +15,7 @@
 Flask==3.0.0
 gunicorn==22.0.0
 Werkzeug==3.0.3
-langchain==0.1.9
+langchain==0.3.0
 sentence-transformers==2.5.1
 text_generation==0.6.1
 google-cloud-dlp==3.12.2