fix(argo-cd): fix ArgoAppNotSynced PrometheusRule annotation template syntax (#3853)

The example ArgoAppNotSynced alert annotations used Helm raw-string
escaping ({{`{{$labels.name}}`}}) which is not processed by Helm when
the PrometheusRule spec is rendered via toYaml. As a result, Prometheus
receives the backtick-escaped form literally and evaluates it as a Go
template raw-string action, outputting {{$labels.name}} verbatim rather
than the actual app name.

Alertmanager then receives {{$labels.name}} as an annotation value.
Since alertmanager 0.30.0, the default PagerDuty details template uses
toJson on the firing alerts and DeepCopyWithTemplate recursively
re-renders all strings in the result. This causes alertmanager to fail
with "undefined variable $labels" because $labels is Prometheus template
syntax, not alertmanager template syntax.

Fix by using plain Prometheus template syntax {{ $labels.name }} which
passes through toYaml unchanged, is rendered correctly by Prometheus,
and reaches alertmanager as a plain string.

Also fix an unclosed bracket in the description annotation.

Signed-off-by: Vincent Rivellino <github@vince-riv.io>

Author: vrivellino

charts/argo-cd/Chart.yaml

@@ -3,7 +3,7 @@ appVersion: v3.3.8
 kubeVersion: ">=1.25.0-0"
 description: A Helm chart for Argo CD, a declarative, GitOps continuous delivery tool for Kubernetes.
 name: argo-cd
-version: 9.5.4
+version: 9.5.5
 home: https://github.com/argoproj/argo-helm
 icon: https://argo-cd.readthedocs.io/en/stable/assets/logo.png
 sources:
@@ -26,5 +26,5 @@ annotations:
     fingerprint: 2B8F22F57260EFA67BE1C5824B11F800CD9D2252
     url: https://argoproj.github.io/argo-helm/pgp_keys.asc
   artifacthub.io/changes: |
-    - kind: changed
-      description: Set argo-cd parent repo as first source in Chart.yaml, so renovate can pull changelogs from parent repo.
+    - kind: fixed
+      description: Fix ArgoAppNotSynced PrometheusRule example annotations to use plain Prometheus template syntax instead of Helm raw-string escaping, which caused alertmanager to receive unrendered template expressions.

charts/argo-cd/values.yaml

@@ -1089,9 +1089,9 @@ controller:
       #   labels:
       #     severity: warning
       #   annotations:
-      #     summary: "[{{`{{$labels.name}}`}}] Application not synchronized"
+      #     summary: "[{{ $labels.name }}] Application not synchronized"
       #     description: >
-      #       The application [{{`{{$labels.name}}`}} has not been synchronized for over
+      #       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.