Add extra stop tokens for phi 3 (#1059)

.env.template

@@ -182,7 +182,7 @@ MODELS=`[
       "modelUrl": "https://huggingface.co/microsoft/Phi-3-mini-4k-instruct",
       "preprompt": "",
       "parameters": {
-        "stop": ["</s>", "<|end|>"],
+        "stop": ["</s>", "<|end|>", "<|endoftext|>", "<|assistant|>"],
         "max_new_tokens": 1024,
         "truncate": 3071
       },