Fix check output

assets/common.sh

@@ -32,5 +32,5 @@ check_version() {
         local dateString=$(date +"$dateVersionFormat" -D %d\ %b\ %Y\ %H:%M:%S\ GMT -d "$tmpDateString")
   fi
 
-  echo "$dateString"
+  echo "[{\"ref\":\"$dateString\"}]" | jq .
 }

pipeline.yml

@@ -3,6 +3,7 @@ resource_types:
   type: docker-image
   source:
     repository: pivotalservices/concourse-curl-resource
+    tag: latest
 
 resources:
 - name: single-file