fix(syncer): wrong address operator on transform Patch func (#586)

## What type of PR is this?

/kind bug

## What this PR does / why we need it:

The underlying type of `dest` is `*unstructured.Unstructured`, and the
address operator makes the return value be a pointer to a pointer, which
causes keyFunc `DeletionHandlingMetaNamespaceKeyFunc` to return errors.

pkg/syncer/transform/transform.go

@@ -92,7 +92,7 @@ func Patch(original interface{}, patchText string) (interface{}, error) {
 	if err := json.Unmarshal(modifiedJSON, &dest); err != nil {
 		return nil, errors.Wrap(err, "json decoding error")
 	}
-	return &dest, nil
+	return dest, nil
 }
 
 // Replace function replaces the original data structure with the new one derived from the JSON string.