Changes the protocol on the Visual Studio Marketplace 
button from vscode to vscode-insiders.
You will need to install a Userscript extension - these ones I tested locally with success:
- Tampermonkey - Chrome Web Store
- Violentmonkey - Chrome Web Store
- Greasemonkey :: Add-ons for Firefox
Once installed, open vscode-protocol-insider.user.js - and install the script. To turn it off, disable it via the extension