[ci] Fixed image snytax : => .

Author: brandongrohmann

ci/tasks/update-release.yml

@@ -4,8 +4,8 @@ platform: linux
 image_resource:
   type: registry-image
   source:
-    repository: ((image/concourse_go:url))
-    tag:        ((image/concourse_go:tag))
+    repository: ((image/concourse_go.url))
+    tag:        ((image/concourse_go.tag))
 
 inputs:
 - name: git