Use a verified publisher on the VS Code Marketplace for the official extension

### Problem statement

Right now if you install the extension from VS Code's marketplace, you get the following message:

It would be nice if this extension, being the official one, used a [verified publisher](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#verify-a-publisher). This would give the blue checkmark as well, making it much more obvious which one to try using first.

Right now the list of extensions look like this:

### Proposed solution

I think it goes something like this:

1. [Create a publisher](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#create-a-publisher)
2. [Verify that publisher](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#verify-a-publisher) with godotengine.org
3. Update the publisher in `package.json`
4. Republish

There's also a [link here](https://code.visualstudio.com/api/working-with-extensions/publishing-extension#i-need-help-with-my-vs-marketplace-account-or-support-in-publishing-an-extension) to get help from the marketplace team if running into any issues.