v9 API support

[qin-guan]

Hey! Thanks for the insane work on this library! I'm not looking for v9 support as of yet but thought to create an issue first to keep track since upstream Telegram.Bot just released support in v22.5!

[niklasweimann]

Hey 👋
Thanks so much for your interest in this library! Support for v9 is definitely on my radar, and I’ll work on adding it as soon as I get the chance.