Function official_json_cache_path 

pub fn official_json_cache_path(
    repo: &str,
    arch: &str,
    pkg_name: &str,
) -> PathBuf

What: Get the path to a cached official package JSON file.

Inputs:

• repo: Repository name.
• arch: Architecture.
• pkg_name: Package name.

Output:

• PathBuf to the cache file.

Details:

• Creates a deterministic filename from repo, arch, and package name.