longhorn: upgrade from 1.9.0 to 1.12.0 (with intermediate releases)

Change-Id: Ice8f4e8f7e073023ab274c83154d9368525f9231
diff --git a/charts/longhorn/templates/servicemonitor.yaml b/charts/longhorn/templates/servicemonitor.yaml
index 3f32961..df98bd6 100644
--- a/charts/longhorn/templates/servicemonitor.yaml
+++ b/charts/longhorn/templates/servicemonitor.yaml
@@ -15,6 +15,9 @@
     {{- toYaml . | nindent 4 }}
   {{- end }}
 spec:
+  {{- with .Values.metrics.serviceMonitor.sampleLimit }}
+  sampleLimit: {{ . }}
+  {{- end }}
   selector:
     matchLabels:
       app: longhorn-manager