TLS1.3: Add Encrypted Extensions

Signed-off-by: XiaokangQian <xiaokang.qian@arm.com>
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index fa2429d..6bdb7ac 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -486,6 +486,7 @@
 #define MBEDTLS_SSL_HS_SERVER_HELLO             2
 #define MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST     3
 #define MBEDTLS_SSL_HS_NEW_SESSION_TICKET       4
+#define MBEDTLS_SSL_HS_ENCRYPTED_EXTENSION      8 // NEW IN TLS 1.3
 #define MBEDTLS_SSL_HS_CERTIFICATE             11
 #define MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE     12
 #define MBEDTLS_SSL_HS_CERTIFICATE_REQUEST     13