Write script to update copyrights

util/update-copyrights.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# Copyright (c) 2016-2022 The Hush developers
+# Released under the GPLv3
+
+# Usage: update-copyrights.sh 2021 2022
+# TODO: verify $1 and $2 exist
+# TODO: verify ack and xargs exist on this system
+
+ack -l -i "201.-202.*Hush dev" | xargs ./util/replace.pl -$1 -$2