fix(yarn): search parent directories for yarn configuration

[jaylindquist]

Changes

Yarn searches for configuration files in parent directories

• .yarnrc: "Yarn will merge .yarnrc files up the file tree."
• .yarnrc.yml: "While Yarn will automatically find them in the parent directories, they should usually be kept at the root of your project (often your repository)"

This can affect the URL when searching for dependencies in custom registries when the package.json file is in a subdirectory while the yarn configuration is in a parent directory.

This change will search for yarn configuration files in parent directories when extracting dependencies for the npm manager.

Context

We have some teams that have a repository similar to the following structure

.
├── .yarnrc
├── package.json
└── projectA/
    └── package.json

The .yarnrc file includes an internal registry while projectA/package.json includes the internal dependency. Currently, renovate can't find the internal dependency because it will search the default registry as the configuration file is in the parent directory.

Yarn will search parent directories for configurations, so when running yarn install it will install the dependency correctly. This change updates the search for yarn configuration files to include parent directories

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please select one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[renovate-release]

🎉 This PR is included in version 37.387.3 🎉

The release is available on:

• GitHub release
• npm package (@latest dist-tag)
• 37.387.3

Your semantic-release bot 📦🚀