How to automatically send notification mail after backup has been completed?

Operating system

Windows

Joplin version

3.0.15

Desktop version info

Joplin 3.0.15 (prod, win32)

Client ID: 472fca95be0c4e30b7de0378e5c577e4
Sync Version: 3
Profile Version: 47
Keychain Supported: Yes

Revision: 598677b

Backup: 1.4.1
Favorites: 1.3.2

Sync target

Joplin Server

Editor

Rich Text Editor

What issue do you have?

I have the backup plugin installed and it works perfectly as scheduled. However, I don't know how to make Joplin automatically send notification mail after a backup has been completed.
Need advice.