@Rishabhh17 no need to downgrade anything you can use it easily. You just need to update one thing that’s it
For less than 2.X
“https://cdn.jsdelivr.net/npm/rasa-webchat@1.0.0/lib/index.js”),
For Greater than 2.X or latest
“https://cdn.jsdelivr.net/npm/rasa-webchat@1.0.1/lib/index.js”),
Note:
@Rishabhh17
Version 1.0.1 of the rasa webchat is made to work with version 2.3.x and 2.4.x of rasa or latest and less then that Use 1.0.0 for other rasa versions.
Now, start working 
Hope you answer my questions from above post too? Good Luck!
I hope it make sense now?