ci: install lockbud on image

Will be used to try detecting deadlocks, see https://github.com/BurtonQin/lockbud

Adding this job as experimenetal for now as it currently won't fail if a deadlock is detected and there is no way to discard false positives, see https://github.com/BurtonQin/lockbud/issues/74

I still think it can be useful to manually check its output (probably more valuable in gst-plugins-rs). See for example https://gitlab.freedesktop.org/gdesmott/gstreamer-rs/-/jobs/67138208 where I added a deadlock for testing.