release: fix tag script
release: fix tag script

The tag script, when not run interactively, will fail without a provided commit
message (since it now uses annotated tags). For now, use a trivial message. In
the future, this could be extended to provide automated release notes.

PiperOrigin-RevId: 281112651

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor