Update pre-requirements.txt

pre-requirements.txt

@@ -5,8 +5,8 @@ llama-index-embeddings-huggingface==0.2.1
 llama-index-embeddings-instructor==0.1.3
 llama-index-vector-stores-faiss==0.1.2
 llama-index-retrievers-bm25==0.1.4
-install llama-index-vector-stores-chroma==0.1.10
-install chromadb==0.5.5
+llama-index-vector-stores-chroma==0.1.10
+chromadb==0.5.5
 numpy==1.23
 scipy==1.8.0
 watchdog