Added webp mime type (useful when downloading stickers)
Added webp mime type (useful when downloading stickers)

expectocode/Telethon,LonamiWebs/Telethon,andr-04/Telethon,kyasabu/Telethon,LonamiWebs/Telethon,LonamiWebs/Telethon,LonamiWebs/Telethon