chore(deps-dev): Bump langgraph from 0.2.15 to 0.2.16 (#75)

Bumps [langgraph](https://github.com/langchain-ai/langgraph) from 0.2.15 to 0.2.16.
- [Release notes](https://github.com/langchain-ai/langgraph/releases)
- [Commits](langchain-ai/langgraph@0.2.15...0.2.16)

---
updated-dependencies:
- dependency-name: langgraph
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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