Update app.py

add revision info for models.

app.py

@@ -39,11 +39,12 @@ Based on the [Norod78/OpenELM_3B_Demo](https://huggingface.co/spaces/Norod78/Ope
 
 model = AutoModelForCausalLM.from_pretrained(
     "apple/OpenELM-270M-Instruct",
+    revision="eb111ff",    
     trust_remote_code=True,
 )
 tokenizer = AutoTokenizer.from_pretrained(
-#    "NousResearch/Llama-2-7b-hf",
-    "meta-llama/Llama-2-7b-hf",    
+    "meta-llama/Llama-2-7b-hf",
+    revision="01c7f73"
     trust_remote_code=True,
     tokenizer_class=LlamaTokenizer,
 )