We want to ensure that the jobs updating the `latest` tags always reflect
the actual latest pipeline.

When two pipelines are started at the same time on the same branch
sometimes the earlier one can complete last due to scheduling or any
other reason, thus breaking the previous assumption.

To avoid that, make the whole pipeline interruptible up to the tagging jobs
so that earlier pipelines get killed when a new one is started.

Signed-off-by: Emanuele Aina <emanuele.aina@collabora.com>