feat: update site doc

Signed-off-by: zufardhiyaulhaq <zufardhiyaulhaq@gmail.com>

site/content/en/latest/api/extension_types.md

@@ -443,6 +443,7 @@ _Appears in:_
 
 | Field | Type | Required | Description |
 | ---   | ---  | ---      | ---         |
+| `requiredClientCertificate` | _boolean_ |  false  | RequiredClientCertificate set to true means that Envoy will reject connections without a valid client certificate. |
 | `caCertificateRefs` | _[SecretObjectReference](https://gateway-api.sigs.k8s.io/references/spec/#gateway.networking.k8s.io/v1.SecretObjectReference) array_ |  false  | CACertificateRefs contains one or more references to<br />Kubernetes objects that contain TLS certificates of<br />the Certificate Authorities that can be used<br />as a trust anchor to validate the certificates presented by the client.<br /><br />A single reference to a Kubernetes ConfigMap or a Kubernetes Secret,<br />with the CA certificate in a key named `ca.crt` is currently supported.<br /><br />References to a resource in different namespace are invalid UNLESS there<br />is a ReferenceGrant in the target namespace that allows the certificate<br />to be attached. |