Revert "fix(kustomize): Deploy latest system-upgrade-controller" (rancher#304)

* Revert "fix(kustomize): Deploy latest system-upgrade-controller"
  This reverts commit 4e31e5d.
* Apply suggestions from code review

Co-authored-by: Brad Davidson <[email protected]>

Author: onno204

kustomization.yaml

@@ -5,3 +5,6 @@ resources:
 - manifests/clusterrole.yaml
 - manifests/clusterrolebinding.yaml
 - manifests/system-upgrade-controller.yaml
+images:
+- name: rancher/system-upgrade-controller
+  newTag: v0.14.0

manifests/system-upgrade-controller.yaml

@@ -66,7 +66,7 @@ spec:
           effect: "NoExecute"
       containers:
         - name: system-upgrade-controller
-          image: rancher/system-upgrade-controller:latest
+          image: rancher/system-upgrade-controller:v0.14.0
           imagePullPolicy: IfNotPresent
           securityContext:
             runAsNonRoot: true