feat(argocd-image-updater): Introduce chart signing (#2046)

Signed-off-by: Marco Kilchhofer <mkilchhofer@users.noreply.github.com>

charts/argocd-image-updater/Chart.yaml

@@ -2,7 +2,7 @@ apiVersion: v2
 name: argocd-image-updater
 description: A Helm chart for Argo CD Image Updater, a tool to automatically update the container images of Kubernetes workloads which are managed by Argo CD
 type: application
-version: 0.9.0
+version: 0.9.1
 appVersion: v0.12.2
 home: https://github.com/argoproj-labs/argocd-image-updater
 icon: https://argocd-image-updater.readthedocs.io/en/stable/assets/logo.png
@@ -14,6 +14,9 @@ maintainers:
   - name: argoproj
     url: https://argoproj.github.io/
 annotations:
+  artifacthub.io/signKey: |
+    fingerprint: 2B8F22F57260EFA67BE1C5824B11F800CD9D2252
+    url: https://argoproj.github.io/argo-helm/pgp_keys.asc
   artifacthub.io/changes: |
-    - kind: fixed
-      description: add namespace field for namespace scoped resources
+    - kind: added
+      description: Introduce chart signing