Add wildcard example (#9164)

* Add wildcard example

* Update wildcard example

certbot-dns-digitalocean/certbot_dns_digitalocean/__init__.py

@@ -77,6 +77,15 @@ Examples
      -d example.com \\
      -d www.example.com
 
+.. code-block:: bash
+   :caption: To acquire a wildcard certificate for ``*.example.com``
+
+   certbot certonly \\
+     --dns-digitalocean \\
+     --dns-digitalocean-credentials ~/.secrets/certbot/digitalocean.ini \\
+     -d example.com \\
+     -d '*.example.com'
+
 .. code-block:: bash
    :caption: To acquire a certificate for ``example.com``, waiting 60 seconds
              for DNS propagation