Publish VS Code extension on Open VSX registry

[marcel-22]

Could you please publish the sphinx-needs-vscode extension, and any future updates, on the Open VSX registry?

The VS Code Marketplace is for use with Microsoft Visual Studio products only. The Open VSX Registry is a community driven and fully open platform for publishing and consuming VS Code extensions. Our development environment is forced to use this registry instead of the Microsoft marketplace.

[marcel-22]

Thanks for the release version 0.3.1 !
Could you perhaps add it to Open VSX as well?