Publish ESPHome VSCode plugin to Open VSX

[definitio]

There's a open alternative to the Visual Studio Marketplace - Open VSX.

As Microsoft's extensions marketplace cannot be used by Code-OSS and VSCodium users for legal reasons, it's probably a good idea to make ESPHome VSCode plugin available to them there.

The publishing process is described in the Open VSX Wiki.

[definitio]

There is unofficial version: https://open-vsx.org/extension/ESPHome/esphome-vscode