Bump langchain from 0.2.1 to 0.2.9

Bumps [langchain](https://github.com/langchain-ai/langchain) from 0.2.1 to 0.2.9.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain==0.2.1...langchain==0.2.9)

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

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

setup-requirements.txt

@@ -1,7 +1,7 @@
 click>=7.0,<9.0
 click-help-colors>=0.9.1,<0.10
 rich>=11.0,<14.0
-langchain==0.2.1
+langchain==0.2.9
 langchain-community==0.2.1
 langchain-core==0.2.1
 langchain-experimental==0.0.59