certbot requires ``--expand`` to add more domains to the cert

nixos/modules/issuer.nix

@@ -195,7 +195,7 @@ in {
           # Register if necessary.
           ${pkgs.certbot}/bin/certbot register ${configArgs} --non-interactive --agree-tos -m ${cfg.letsEncryptAdminEmail} || true
           # Obtain the certificate.
-          ${pkgs.certbot}/bin/certbot certonly ${configArgs} --non-interactive --standalone --domains ${builtins.concatStringsSep "," cfg.domains}
+          ${pkgs.certbot}/bin/certbot certonly ${configArgs} --non-interactive --standalone --expand --domains ${builtins.concatStringsSep "," cfg.domains}
           '';
       };
     };