With commit 673f23c was the libdns added to Dataplane API.
Please can you be so kind and add https://github.com/libdns/desec to the list of the providers https://github.com/haproxytech/dataplaneapi/blob/master/acme/dns01-providers.txt
I run the ACME dns-01 test with that provider and added an issue to haproxy haproxy/haproxy#3193 and it would be nice to be able to test the ACME dns-01 with that provider within dataplaneapi.