qapi: fix examples of events missing timestamp

I've used real timestamp and changing them one by one so they would
not be all equal.

Problem was noticed when using the example as a test case for Go
bindings.

Signed-off-by: Victor Toso <victortoso@redhat.com>
Message-Id: <20220901085840.22520-11-victortoso@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>