fix: add missing TLS 1.3 support

Author: kenjis

system/Email/Email.php

@@ -1883,7 +1883,7 @@ protected function SMTPConnect()
             $crypto = stream_socket_enable_crypto(
                 $this->SMTPConnect,
                 true,
-                STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
+                STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_3_CLIENT
             );
 
             if ($crypto !== true) {