The Let’s Encrypt add-on doesn’t have support for acme-dns. This is a self-hosted provider for the DNS-challenge.
Python already has a library for it:
I think adding this to the corresponding Dockerfile might be sufficient.
It would be awesome if you would consider it.
If you are really interested in this feature, then I suggest you vote for it yourself as a start.
Me too would like to see ACME-DNS support into Let’s Encrypt Add-on. How many votes would it need to get it included? Should we create a HA Add-on feature ticket for it?