chore(deps): Bump langchain

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.2.14 to 0.2.15.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==0.2.14...langchain==0.2.15)

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

Signed-off-by: dependabot[bot] <support@github.com>

examples/langchain/langchainpy-localai-example/requirements.txt

@@ -10,7 +10,7 @@ debugpy==1.8.2
 frozenlist==1.4.1
 greenlet==3.0.3
 idna==3.8
-langchain==0.2.14
+langchain==0.2.15
 langchain-community==0.2.12
 marshmallow==3.22.0
 marshmallow-enum==1.5.1