public static boolean isValidRepository(String repository) {
    return repository.matches(REPOSITORY_REGEX);
  }
Returns {@code true} if {@code repository} is a valid repository string. For example, a valid
repository string could be {@code my-repository} or {@code k8s-skaffold/skaffold}.

@param repository the repository to check
@return {@code true} if is a valid repository; {@code false} otherwise
jib-core/src/main/java/com/google/cloud/tools/jib/api/ImageReference.java