Yarn 2 and Yarn 3 support in Dependabot updates

[github-product-roadmap]

Summary

This item adds support for updating Yarn 2 and Yarn 3 dependencies automatically using Dependabot.

Intended Outcome

Dependabot can currently generate pull requests for repositories that use Yarn 1, but it does not support either Yarn 2 or Yarn 3. Later versions of Yarn have seen increasing adoption, so it's important that we support these to help developers stay on secure versions of their dependencies.

How will it work?

No response

[ankneis]

🚢 This has shipped: https://github.blog/changelog/2022-10-20-dependabot-can-now-generate-security-and-version-updates-for-yarn-v2-and-v3/