Publish extension to Open VSX

[madeindjs]

You may want to add this extension to Open VSX to make it available for VSCodium

Open VSX is a vendor-neutral open-source alternative to the Visual Studio Marketplace. It provides a server application that manages VS Code extensions in a database, a web application similar to the VS Code Marketplace, and a command-line tool for publishing extensions similar to vsce. - eclipse/openvsx: An open-source registry for VS Code extensions

To publish it, you simply have to follow this guide.