Update Helm release longhorn to v1.12.0

Author: renovate[bot]

apps/longhorn/helmfile.yaml.gotmpl

@@ -5,5 +5,5 @@ repositories:
 releases:
   - name: longhorn
     chart: longhorn/longhorn
-    version: 1.10.1
+    version: 1.12.0
     namespace: longhorn-system