Update examples in README to be compatible with soon-to-come ChatWidget

See https://github.com/huggingface/huggingface.js/pull/510.

README.md

@@ -8,7 +8,12 @@ datasets:
 language:
 - en
 widget:
-- text: "<|system|>\nYou are a chatbot who can help code!</s>\n<|user|>\nWrite me a function to calculate the first 10 digits of the fibonacci sequence in Python and print it out to the CLI.</s>\n<|assistant|>\n"
+  - example_title: Fibonacci (Python)
+    messages:
+    - role: system
+      content: You are a chatbot who can help code!
+    - role: user
+      content: Write me a function to calculate the first 10 digits of the fibonacci sequence in Python and print it out to the CLI.
 ---
 <div align="center">