chore(deps): update dependency rancher/system-upgrade-controller to v0.15.2

Author: renovate[bot]

cluster/apps/system-upgrade/system-upgrade-controller/kustomization.yaml

@@ -2,7 +2,7 @@
 apiVersion: kustomize.config.k8s.io/v1beta1
 kind: Kustomization
 resources:
-  - github.com/rancher/system-upgrade-controller?ref=v0.9.1
+  - github.com/rancher/system-upgrade-controller?ref=v0.15.2
   - plans
 images:
   - name: rancher/system-upgrade-controller