fix licence

Signed-off-by: Gilberto Conti <g.conti@arduino.cc>

Author: gibix

libraries/Arduino_OTA/examples/OTA_WiFi/arduino_secrets.h

@@ -1,2 +1,8 @@
+/*
+ * Copyright (c) Arduino s.r.l. and/or its affiliated companies
+ *
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ */
+
 #define SECRET_SSID "your-ssid"
 #define SECRET_PASS "your-password"