charts: Fix imagePullSecrets in value schema

k8s wanted it in a different way, earlier we were validating wrong
input.

Fixes: #2113
Signed-off-by: Kautilya Tripathi <ktripathi@microsoft.com>

charts/headlamp/values.schema.json

@@ -33,9 +33,15 @@
     },
     "imagePullSecrets": {
       "type": "array",
-      "description": "Image pull secrets",
+      "description": "ImagePullSecrets is an optional list of references to secrets in the same namespace to use for pulling any of the images used by this PodSpec. If specified, these secrets will be passed to individual puller implementations for them to use.",
       "items": {
-        "type": "string"
+        "type": "object",
+        "properties": {
+          "name": {
+            "type": "string",
+            "description": "Name of the image pull secret"
+          }
+        }
       }
     },
     "nameOverride": {