Describe the bug
I get this error when I have too many containers that need updating or fail:

Failed to send notification via shoutrrr (url=telegram://1234:AA1234BCDEF@telegram?channels=225533):  message exceeds the max length

The problem is that Telegram does not support messages longer than 4096 characters

Possible solution
A simple fix would be to split the message once it reaches 4096 characters (preferably when there is a newline before the 4096 character, to have it cleaner to see).

To avoid problems with Telegram, you could send a warning message if it is longer than 20(?) messages (4096 * 20 characters), saying that it is impossible to send all notifications because they are too long to display in Telegram, is better than not receiving a warning at all.

To Reproduce
Steps to reproduce the behavior:

1. Create many containers that need to be updated in order to have a long message
2. Wait for the watchtower update check
3. See error

Expected behavior
Receive notifications on Telegram when a message is too long

Environment
I am using containrrr/watchtower:latest image (arm64).
Docker version 20.10.12, build e91ed57