Probably a problem with long polling

Default timeout in [`GetUpdateAsync`](https://github.com/TelegramBots/telegram.bot/blob/develop/src/Telegram.Bot/TelegramBotClient.cs#L409) method is set to 0. `BotManager` should take timeout from `ITelegramBotClient` and pass it to `GetUpdatesAsync` method. I think there also should be a config for timeout in `BotOptions`.