Update docs ImageUpdateAutomation example

Signed-off-by: Aurel Canciu <aurelcanciu@gmail.com>

docs/guides/image-update.md

@@ -260,7 +260,7 @@ spec:
     messageTemplate: '[ci skip] update image'
   interval: 1m0s
   update:
-    setters: {}
+    strategy: Setters
 ```
 
 Commit and push changes to main branch:
@@ -615,4 +615,4 @@ Then create a secret, encrypt it using [Mozilla SOPS](mozilla-sops.md) or [Seale
 
 ### Azure Container Registry
 
-TODO
+TODO