fix stripe-sca doc link

src/main/webapp/resources/angular-templates/admin/partials/configuration/system.html

@@ -198,7 +198,7 @@ <h2>Payment</h2>
                 <div class="alert alert-info">
                     <ul class="list-unstyled">
                         <li><i class="fa fa-info-circle"></i> more info on Stripe API Keys <a rel="noreferrer noopener" href="https://stripe.com/docs/dashboard#api-keys" target="_blank">here</a></li>
-                        <li><i class="fa fa-info-circle"></i> Additionally, please refer to the following <a rel="noreferrer noopener" href="https://github.com/alfio-event/alf.io/blob/master/docs/howto/configuration/stripe-sca/index.md" target="_blank">tutorial</a> if you want to enable Strong Customer Authentication (aka 3DSecure 2.0)</li>
+                        <li><i class="fa fa-info-circle"></i> Additionally, please refer to the following <a rel="noreferrer noopener" href="https://alf.io/docs/configuration/payment/stripe-sca/" target="_blank">tutorial</a> if you want to enable Strong Customer Authentication (aka 3DSecure 2.0)</li>
                     </ul>
                 </div>
                 <div data-ng-repeat="setting in systemConf.paymentStripe.settings">