Change public link to invite link.

Author: eternnoir

README.md

@@ -505,7 +505,7 @@ if message.chat.type == “channel”:
 
 Get help. Discuss. Chat.
 
-* Join the [pyTelegramBotAPI Telegram Chat Group](https://telegram.me/pbtai)
+* Join the [pyTelegramBotAPI Telegram Chat Group](https://telegram.me/joinchat/Bn4ixj84FIZVkwhk2jag6A)
 * We now have a Telegram Channel as well! Keep yourself up to date with API changes, and [join it](https://telegram.me/pytelegrambotapi).
 
 ## More examples