Bump langchain from 0.1.11 to 0.3.0 in /examples/chat-py

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.1.11 to 0.3.0.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-openai==0.1.11...langchain==0.3.0)

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

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

examples/chat-py/requirements.txt

@@ -7,7 +7,7 @@ charset-normalizer==3.1.0
 dataclasses-json==0.5.7
 frozenlist==1.3.3
 idna==3.7
-langchain==0.1.11
+langchain==0.3.0
 marshmallow==3.19.0
 marshmallow-enum==1.5.1
 multidict==6.0.4