GitHub Actions Caching Strategies Mastery Hub: The Industry

In the context of optimizing GitHub Actions caches, what is the primary benefit of leveraging the `cache` action with a `key` that includes a hash of dependency lock files (e.g., `package-lock.json`, `yarn.lock`, `Gemfile.lock`)?

When implementing a strategy for caching build artifacts in GitHub Actions, what is the most effective approach to ensure that only relevant artifacts are cached and that the cache size remains manageable, especially in large monorepos?

Consider a scenario where a GitHub Actions workflow builds a Docker image. What is the most robust and efficient strategy for caching Docker layer data to accelerate subsequent builds of the same or similar images?