fix: write cron in pre-delete phase

plugins/cron/triggers.go

@@ -55,9 +55,24 @@ func TriggerPostAppRenameSetup(oldAppName string, newAppName string) error {
 	return nil
 }
 
+// TriggerPreDelete stops cron for a given app
+func TriggerPreDelete(appName string) error {
+	scheduler := common.GetAppScheduler(appName)
+	_, err := common.CallPlugnTrigger(common.PlugnTriggerInput{
+		Trigger:     "scheduler-cron-write",
+		Args:        []string{scheduler, appName},
+		StreamStdio: true,
+	})
+	return err
+}
+
 // TriggerPostDelete destroys the cron property for a given app container
 func TriggerPostDelete(appName string) error {
-	return common.PropertyDestroy("cron", appName)
+	if err := common.PropertyDestroy("cron", appName); err != nil {
+		return err
+	}
+
+	return nil
 }
 
 // TriggerSchedulerStop stops the scheduler for a given app container