Certbot's ACMEv2 support was not yet present in that release.
Please take a look at this advice from the Certbot team which will advise you on what version you need to be using to get onto ACMEv2.
Unfortunately for you, Ubuntu 17.10 is a non-LTS release and has been EOL for a very long time. You need to get onto one of the releases of Ubuntu which is still supported by Canonical; that will be the most straightforward path to getting up-to-date Certbot software.