Add change log for mbedtls_ssl_session_get_ticket_creation_time()

Signed-off-by: Ronald Cron <ronald.cron@arm.com>
diff --git a/ChangeLog.d/get_ticket_creation_time.txt b/ChangeLog.d/get_ticket_creation_time.txt
new file mode 100644
index 0000000..7b5166c
--- /dev/null
+++ b/ChangeLog.d/get_ticket_creation_time.txt
@@ -0,0 +1,3 @@
+Features
+   * Add getter (mbedtls_ssl_session_get_ticket_creation_time()) to access
+     `mbedtls_ssl_session.ticket_creation_time`.