examples: add upgrade YAML for MicroOS

Signed-off-by: Alberto Planas <aplanas@suse.com>

examples/openSUSE/microos.yaml

+---
+apiVersion: v1
+kind: Secret
+metadata:
+  name: microos
+  namespace: system-upgrade
+type: Opaque
+stringData:
+  upgrade.sh: |
+    #!/bin/sh
+    set -e
+    secrets=$(dirname $0)
+    transactional-update --continue cleanup dup
+    # For a delayed reboot use:
+    #   rebootmgrctl reboot
+    # or chain it with transactional-update commands:
+    #   transactional-update --continue cleanup dup reboot
+    [ -f /run/reboot-needed ] && rebootmgrctl reboot now
+---
+apiVersion: upgrade.cattle.io/v1
+kind: Plan
+metadata:
+  name: microos
+  namespace: system-upgrade
+spec:
+  concurrency: 2
+  nodeSelector:
+    matchExpressions:
+      - {key: node-role.kubernetes.io/worker, operator: In, values: ["true"]}
+  serviceAccountName: system-upgrade
+  secrets:
+    - name: microos
+      path: /host/run/system-upgrade/secrets/microos
+  drain:
+    force: true
+  version: microos
+  upgrade:
+    image: registry.opensuse.org/opensuse/tumbleweed:latest
+    command: ["chroot", "/host"]
+    args: ["sh", "/run/system-upgrade/secrets/microos/upgrade.sh"]