Add Hacktoberfest 2025 banner to README.md

Hi 👋 I came across this repo while looking for Hacktoberfest 2025 projects.

Would you please confirm if this repo is participating or not?

I noticed that the README.md file has the Hacktoberfest 2025 banner missing. 

This will increase visibility and help new contributors.

May I include that if it is okay?

Thank you 😊