IDNA zone is not recognized

Greetings and thanks for the plugin!

Problem

I've encountered a problem with international domain name. When issuing certificate with certbot for international zone (say Δomain.com), one will use an encoded domain name: xn--omain-u9d.com.

This results in

Zone not found for domain xn--omain-u9d.com

Because Selectel will not use proper encoding for zone name in response:

{"name": "Δomain.com", ...}

Proposal

The fix seems to be pretty straight-forward. Script should encode names received from both input and Selectel.

--

Should I take a closer look and then make a PR?