fix: missing country code in invoice template

lnvps_api/invoice.html

@@ -98,6 +98,7 @@
             <div>{{user.state}}</div>
             <div>{{user.postcode}}</div>
             <div>{{user.country}}</div>
+            <div>{{user.country_code}}</div>
             <div>{{user.tax_id}}</div>
         </div>
         {{#company}}
@@ -110,6 +111,7 @@
             <div>{{company.state}}</div>
             <div>{{company.postcode}}</div>
             <div>{{company.country}}</div>
+            <div>{{company.country_code}}</div>
             <div>{{company.tax_id}}</div>
         </div>
         {{/company}}