Chroma init function has been deprecated 

The Chroma init function has been deprecated, the new init function uses `embedding_function` instead of `embeddings` 

```
self.vector_store = Chroma(
                persist_directory="chroma_db", embedding_function=FastEmbedEmbeddings()
            )
```

I have a created a branch with the changes, but I don't have push permissions into the repo. 