autoupdates: Fix to use correct unit

Definitely a brown paper bag bug.

tier-0/autoupdates.yaml

@@ -8,4 +8,4 @@ postprocess:
     target=/usr/lib/systemd/system/default.target.wants
     mkdir -p $target
     set -x
-    ln -s ../bootc-fetch-apply-updates.service $target
+    ln -s ../bootc-fetch-apply-updates.timer $target