[argo-cd] Added simple PrometheusRule (#178)

* [argo-cd] Added simple PrometheusRule
This patch adds a few simple rules which you can leverage to make
sure that your infrastructure is up to date.  They are optional
and opt-in only.
* Add conditional selector fix from #180
* Bump chart version

charts/argo-cd/values.yaml

@@ -111,6 +111,37 @@ controller:
     #     prometheus: kube-prometheus
     #   namespace: monitoring
     #   additionalLabels: {}
+    rules:
+      enabled: false
+      spec: []
+      # - alert: ArgoAppMissing
+      #   expr: |
+      #     absent(argocd_app_info)
+      #   for: 15m
+      #   labels:
+      #     severity: critical
+      #   annotations:
+      #     summary: "[ArgoCD] No reported applications"
+      #     description: >
+      #       ArgoCD has not reported any applications data for the past 15 minutes which
+      #       means that it must be down or not functioning properly.  This needs to be
+      #       resolved for this cloud to continue to maintain state.
+      # - alert: ArgoAppNotSynced
+      #   expr: |
+      #     argocd_app_sync_status{sync_status!="Synced"} == 1
+      #   for: 12h
+      #   labels:
+      #     severity: warning
+      #   annotations:
+      #     summary: "[{{`{{$labels.name}}`}}] Application not synchronized"
+      #     description: >
+      #       The application [{{`{{$labels.name}}`}} has not been synchronized for over
+      #       12 hours which means that the state of this cloud has drifted away from the
+      #       state inside Git.
+    #   selector:
+    #     prometheus: kube-prometheus
+    #   namespace: monitoring
+    #   additionalLabels: {}
 
   ## Enable Admin ClusterRole resources.
   ## Enable if you would like to grant rights to ArgoCD to deploy to the local kuberentes cluster.