Add support for mijn.host DNS plugin

Adds certbot-dns-mijn-host as a DNSPLUGIN option (mijn-host), including
the plugin in both Dockerfiles, a credentials template under
dns-conf, and the DNSPLUGIN list in readme-vars.yml.

Closes #606

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Dockerfile

@@ -121,6 +121,7 @@ RUN \
     certbot-dns-linode \
     certbot-dns-loopia \
     certbot-dns-luadns \
+    certbot-dns-mijn-host \
     certbot-dns-namecheap \
     certbot-dns-netcup \
     certbot-dns-njalla \

Dockerfile.aarch64

@@ -121,6 +121,7 @@ RUN \
     certbot-dns-linode \
     certbot-dns-loopia \
     certbot-dns-luadns \
+    certbot-dns-mijn-host \
     certbot-dns-namecheap \
     certbot-dns-netcup \
     certbot-dns-njalla \

readme-vars.yml

@@ -32,7 +32,7 @@ opt_param_usage_include_env: true
 opt_param_env_vars:
   - {env_var: "SUBDOMAINS", env_value: "www,", desc: "Subdomains you'd like the cert to cover (comma separated, no spaces) ie. `www,ftp,cloud`. For a wildcard cert, set this *exactly* to `wildcard` (wildcard cert is available via `dns` validation only)"}
   - {env_var: "CERTPROVIDER", env_value: "", desc: "Optionally define the cert provider. Set to `zerossl` for ZeroSSL certs (requires existing [ZeroSSL account](https://app.zerossl.com/signup) and the e-mail address entered in `EMAIL` env var). Otherwise defaults to Let's Encrypt."}
-  - {env_var: "DNSPLUGIN", env_value: "cloudflare", desc: "Required if `VALIDATION` is set to `dns`. Options are `acmedns`, `aliyun`, `azure`, `bunny`, `cloudflare`, `cpanel`, `desec`, `digitalocean`, `directadmin`, `dnsimple`, `dnsmadeeasy`, `dnspod`, `do`, `domeneshop`, `dreamhost`, `duckdns`, `dynu`, `freedns`, `gandi`, `gehirn`, `glesys`, `godaddy`, `google`, `he`, `hetzner`, `hetzner-cloud`, `infomaniak`, `inwx`, `ionos`, `linode`, `loopia`, `luadns`, `namecheap`, `netcup`, `njalla`, `nsone`, `ovh`, `porkbun`, `rfc2136`, `route53`, `sakuracloud`, `standalone`, `transip`, and `vultr`. Also need to enter the credentials into the corresponding ini (or json for some plugins) file under `/config/dns-conf`."}
+  - {env_var: "DNSPLUGIN", env_value: "cloudflare", desc: "Required if `VALIDATION` is set to `dns`. Options are `acmedns`, `aliyun`, `azure`, `bunny`, `cloudflare`, `cpanel`, `desec`, `digitalocean`, `directadmin`, `dnsimple`, `dnsmadeeasy`, `dnspod`, `do`, `domeneshop`, `dreamhost`, `duckdns`, `dynu`, `freedns`, `gandi`, `gehirn`, `glesys`, `godaddy`, `google`, `he`, `hetzner`, `hetzner-cloud`, `infomaniak`, `inwx`, `ionos`, `linode`, `loopia`, `luadns`, `mijn-host`, `namecheap`, `netcup`, `njalla`, `nsone`, `ovh`, `porkbun`, `rfc2136`, `route53`, `sakuracloud`, `standalone`, `transip`, and `vultr`. Also need to enter the credentials into the corresponding ini (or json for some plugins) file under `/config/dns-conf`."}
   - {env_var: "PROPAGATION", env_value: "", desc: "Optionally override (in seconds) the default propagation time for the dns plugins."}
   - {env_var: "EMAIL", env_value: "", desc: "Optional e-mail address used for cert expiration notifications (Required for ZeroSSL)."}
   - {env_var: "ONLY_SUBDOMAINS", env_value: "false", desc: "If you wish to get certs only for certain subdomains, but not the main domain (main domain may be hosted on another machine and cannot be validated), set this to `true`"}
@@ -219,6 +219,7 @@ init_diagram: |
   "swag:latest" <- Base Images
 # changelog
 changelogs:
+  - {date: "19.06.26:", desc: "Add support for mijn.host dns validation."}
   - {date: "01.06.26:", desc: "Remove obsolete old cert check logic."}
   - {date: "23.01.26:", desc: "Reorder init to fix proxy conf version checks."}
   - {date: "21.12.25:", desc: "Add support for hetzner-cloud dns validation."}

root/defaults/dns-conf/mijn-host.ini

@@ -0,0 +1,3 @@
+# Instructions: https://github.com/mijnhost/certbot-dns-mijn-host
+# Replace with your API key from your mijn.host account.
+dns_mijn_host_api_key = yourapikeygoeshere