yarn: migrate private registry from version 1 config to version 3

Let's say that you have a package from your private registry @your-company/awesome-lib

Before

.npmrc

//your.company.com/private/registry/:_authToken=token

.yarnrc

"@your-company:registry" "//your.company.com/private/registry/"

After

.yarnrc.yml

nodeLinker: node-modules # This line should be created automatically.
npmRegistries:
  //your.company.com/private/registry/:
    npmAuthToken: "token"
npmScopes:
  your-company:
    npmPublishRegistry: "https://your.company.com/private/registry"
    npmRegistryServer: "https://your.company.com/private/registry"