I'm trying to better understand how the cache works within RenovateBot, especially regarding the use of GitHub's built-in cache action, and I have a few specific questions:

Cache Contents: Does the RenovateBot cache contain only internal Renovate data, or does it also store repository-specific information like package.json, package-lock.json, or other configuration files? I noticed that the examples in the documentation use a static cache key. How does this affect the cache's contents?

Ideal Cache Key for Frontend JS Packages: For a typical frontend JS package, what would an ideal cache key look like? Would it be static or dynamic, potentially generated by hashing the package.json and package-lock.json files, or is there another approach that’s recommended? Are there best practices for creating cache keys for these kinds of repositories to improve cache efficiency?

Built-in Action Cache Limitations: I understand from the docs that using the built-in GitHub Action cache has limitations. Specifically, it mentions that the cache key needs to be computed from a file within the cache, and that this leads to issues where there might not be data to restore or upload. Could you please elaborate on why the built-in cache action isn't ideal for RenovateBot? What specific problems arise when trying to use actions/cache?