feat: add system upgrade controller

cluster/apps/system-upgrade/system-upgrade-controller/agent-plan.yaml

@@ -0,0 +1,25 @@
+---
+apiVersion: upgrade.cattle.io/v1
+kind: Plan
+metadata:
+  name: k3s-agent
+  namespace: system-upgrade
+  labels:
+    k3s-upgrade: agent
+spec:
+  serviceAccountName: system-upgrade
+  concurrency: 1
+  channel: https://update.k3s.io/v1-release/channels/v1.20
+  nodeSelector:
+    matchExpressions:
+    - key: node-role.kubernetes.io/master
+      operator: NotIn
+      values:
+      - "true"
+  prepare:
+    image: rancher/k3s-upgrade
+    args:
+    - "prepare"
+    - "k3s-server"
+  upgrade:
+    image: rancher/k3s-upgrade

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

@@ -0,0 +1,6 @@
+---
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+- server-plan.yaml
+- agent-plan.yaml

cluster/apps/system-upgrade/system-upgrade-controller/server-plan.yaml

@@ -0,0 +1,22 @@
+---
+apiVersion: upgrade.cattle.io/v1
+kind: Plan
+metadata:
+  name: k3s-server
+  namespace: system-upgrade
+spec:
+  serviceAccountName: system-upgrade
+  concurrency: 1
+  channel: https://update.k3s.io/v1-release/channels/v1.20
+  cordon: true
+  nodeSelector:
+    matchExpressions:
+    - key: node-role.kubernetes.io/master
+      operator: In
+      values:
+      - "true"
+  tolerations:
+  - key: "node-role.kubernetes.io/master"
+    operator: "Exists"
+  upgrade:
+    image: rancher/k3s-upgrade