Update d.json

[JohhannasReyn]

Added DuplExpellio to the plugin repository

• I'm the package's author and/or maintainer.
• I have read the docs.
• I have tagged a release with a server version number.
• My package repo has a description and a README describing what it's for and how to use it.
• My package doesn't add context menu entries. *
• My package doesn't add key bindings. **
• Any commands are available via the command palette.
• Preferences and keybindings (if any) are listed in the menu and the command palette, and open in split view.

My package is ...

There are no packages like it in Package Control. <--- This one