Add default chat template to tokenizer_config.json

[Automated] This PR adds the default chat template to the tokenizer config, allowing the model to be used with the new conversational widget (see [PR](https://github.com/huggingface/huggingface.js/pull/457)).

If the default is not appropriate for your model, please set `tokenizer.chat_template` to an appropriate template. See https://huggingface.co/docs/transformers/main/chat_templating for more information.

tokenizer_config.json

@@ -1 +1,12 @@
-{"max_len": 1024, "bos_token": "<bos>", "eos_token": "<eos>", "unk_token": "<|endoftext|>", "pad_token": "<pad>", "additional_special_tokens": ["<speaker1>", "<speaker2>"]}
+{
+  "max_len": 1024,
+  "bos_token": "<bos>",
+  "eos_token": "<eos>",
+  "unk_token": "<|endoftext|>",
+  "pad_token": "<pad>",
+  "additional_special_tokens": [
+    "<speaker1>",
+    "<speaker2>"
+  ],
+  "chat_template": "{% for message in messages %}{{ message.content }}{{ eos_token }}{% endfor %}"
+}