Command "show" failed: [Composer\Downloader\TransportException] The 'https://repo.magento.com/packages.json' URL required authentication. You must be using the interactive console to authenticate show [--all] [-i|--installed] [-p|--platform] [-a|--available] [-s|--self] [-N|--name-only] [-P|--path] [-t|--tree] [-l|--latest] [-o|--outdated] [-m|--minor-only] [-D|--direct] [--strict] [-f|--format FORMAT] [--] [<package>] [<version>]
i've got the same error.
So i'm looking for a solution, if you have found since 2018, please give it here.
Thanks
Same question here...