gsi-pubsign-release.sh: Add copyright notice

Bug: 149803895
Test: manual
Merged-In: I7208b928fd13ede982a06205badeb4800d5cbb85
Change-Id: I7208b928fd13ede982a06205badeb4800d5cbb85
(cherry picked from commit 06cc62e141c63008f584f46c071db7565023d14e)
1 file changed