ssh-key-action/node_modules/npm-check-updates/lib/package-managers/README.md

To add support for another package manager, drop in a module with the following interface:

{
    list: (npmOptions) => Promise<{ NAME: VERSION, ... }>
    latest: (String pkgName) => Promise<String> version
    newest: (String pkgName) => Promise<String> version
    greatest: (String pkgName) => Promise<String> version
    greatestMajor: (String pkgName, String currentVersion) => Promise<String> version
    greatestMinor: (String pkgName, String currentVersion) => Promise<String> version
}

• latest and greatest are expected to reject with '404 Not Found' if the package is not found