docs: update example homepage widget to conform to latest config spec

Co-authored-by: Valdr687 <106614142+Valdr687@users.noreply.github.com>

docs/src/content/docs/community-resources/homepage-widget.mdx

@@ -55,24 +55,20 @@ widget:
   refreshInterval: 10000
   method: GET
   mappings:
-    - field:
-        metrics: monitored_images
+    - field: metrics.monitored_images
       label: Monitored images
       format: number
-    - field:
-        metrics: up_to_date
+    - field: metrics.up_to_date
       label: Up to date
       format: number
-    - field:
-        metrics: updates_available
+    - field: metrics.updates_available
       label: Available updates
       format: number
-    - field:
-        metrics: unknown
+    - field: metrics.unknown
       label: Unknown
       format: number
 ```
 
 Preview:
 <Image src={widget2} />
-Credit: [@remussamoila](https://github.com/remussamoila)
+Credit: [@remussamoila](https://github.com/remussamoila) and [@Valdr687](https://github.com/Valdr687)