chore(deps): bump langchain-chroma from 0.1.1 to 0.1.2 in /backend

Bumps [langchain-chroma](https://github.com/langchain-ai/langchain) from 0.1.1 to 0.1.2.
- [Release notes](https://github.com/langchain-ai/langchain/releases)
- [Commits](https://github.com/langchain-ai/langchain/compare/langchain-chroma==0.1.1...langchain-chroma==0.1.2

)

---
updated-dependencies:
- dependency-name: langchain-chroma
  dependency-type: direct:production
  update-type: version-update:semver-patch
...
Signed-off-by: dependabot[bot] <support@github.com>

backend/requirements.txt

@@ -32,7 +32,7 @@ google-generativeai==0.5.4
 
 langchain==0.2.0
 langchain-community==0.2.0
-langchain-chroma==0.1.1
+langchain-chroma==0.1.2
 
 fake-useragent==1.5.1
 chromadb==0.5.0