Yarn 2 "Unrecognized or legacy configuration settings found" npmScopes and npmRegistries

Bug description

In a fresh install of yarn 2 in an otherwise empty project, I am getting an “Unrecognized or legacy configuration settings found” for my npmScopes and npmRegistries settings in my .yarnrc.yml file. Here are the contents of the file (with the token replaced):

yarnPath: ".yarn/releases/yarn-berry.cjs"
npmScopes:
	gsap:
		npmRegistryServer: "https://npm.greensock.com"
npmRegistries: 
	//npm.greensock.com:
		npmAlwaysAuth: true
		npmAuthToken: "TOKEN-GOES-HERE"

What is the current behavior? Yarn errors at the gsap or //npm.greensock.com: lines (depending which one I put first in the file). It seems like I’m doing it correctly according to the docs. Has something changed?

What is the expected behavior? I expect it to install GSAP from the given private registry.

Using NPM I can install this by adding the following to my .npmrc file:

//npm.greensock.com/:_authToken=TOKEN-GOES-HERE
@gsap:registry=https://npm.greensock.com

and installing via npm install gsap@npm:@gsap/business

Environment

• Yarn v1 Version: 1.22.10
• OS and version: Catalina