* @return filenames for changelog files in previous releases, without any path
     */
    private static Set<String> findAllFilesInEarlierVersions(GitWrapper gitWrapper, QualifiedVersion version) {
        return findPreviousVersion(gitWrapper, version)
            .flatMap(earlierVersion -> gitWrapper.listFiles("v" + earlierVersion, "docs/changelog"))
            .map(line -> Path.of(line).getFileName().toString())