function getPublishTime(entry) {
            if (entry.versions) {
                return new Date(entry.versions[entry.versions.length - 1].published).getTime();
            }

            return Number.NEGATIVE_INFINITY;
        }
Returns an array of current registry entries, sorted by the publish date of the latest version of each entry.
@param {object} registry The unsorted registry.
@param {string} subkey The subkey to look for the registry metadata in. If unspecified, assumes
    we should look at the top level of the object.
@return {Array} Sorted array of registry entries.