fix: copyright for wallet_upgradetohd.py

Author: knst

test/functional/wallet_upgradetohd.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-# Copyright (c) 2016 The Bitcoin Core developers
+# Copyright (c) 2016-2025 The Dash Core developers
 # Distributed under the MIT software license, see the accompanying
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 """