Bump langchain-openai from 0.1.7 to 0.1.21

Bumps [langchain-openai](https://github.com/langchain-ai/langchain) from 0.1.7 to 0.1.21.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](langchain-ai/langchain@langchain-openai==0.1.7...langchain-openai==0.1.21)

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

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

setup-requirements.txt

@@ -5,6 +5,6 @@ langchain==0.2.1
 langchain-community==0.2.1
 langchain-core==0.2.1
 langchain-experimental==0.0.59
-langchain-openai==0.1.7
+langchain-openai==0.1.21
 langchain-text-splitters==0.2.0
 langchainhub==0.1.16