update changelog - mention perplexity

README.md

@@ -9,6 +9,7 @@ Pardon My English is designed to assist non-native English speakers by transform
 
 # Changelog
 
+- \[2024-05-28\] We've added support for the Perplexity API, which now integrates with Llama3-70b-instruct. When selected, it adheres more closely to the initial instructions.
 - \[2024-05-25\] We've added an alternative frontend. Instead of using Telegram, you can now run the app locally by using `streamlit run frontend.py` command, and interact with Pardon My English in the same way as before.
 - \[2024-04-24\] We've transitioned to using Llama3-70B for all existing and new users, and have seen significant improvements in quality without any degradation in inference speed, thanks to the capabilities of [Groq](https://groq.com/).