ISSUE-1360: change to looking for lower-case reponse from dockerhub when tag isnt present.

The response for an image tag that has not been found is inside a JSON elemnt of "message" not the stated "details", it has also been lower-cased.

Signed-off-by: Alistair Hey <alistair.hey@gmail.com>

contrib/publish-arm.sh

@@ -48,13 +48,13 @@ do
 
    for IMAGE in "${images[@]}"
    do
-      TAG_PRESENT=$(curl -s "https://hub.docker.com/v2/repositories/${IMAGE}/tags/${TAG}-${ARM_VERSION}/" | grep -Po '"detail": *"[^"]*"' | grep -o 'Not found')
-      if [ "$TAG_PRESENT" = "Not found" ]; then
+      TAG_PRESENT=$(curl -s "https://hub.docker.com/v2/repositories/${IMAGE}/tags/${TAG}-${ARM_VERSION}/" | grep -Po '"message": *"[^"]*"' | grep -io 'not found')
+      if [ "$TAG_PRESENT" = "not found" ]; then
       break
       fi
    done
    
-   if [ "$TAG_PRESENT" = "Not found" ]; then
+   if [ "$TAG_PRESENT" = "not found" ]; then
        make ci-${ARM_VERSION}-build ci-${ARM_VERSION}-push
    else
      for IMAGE in "${images[@]}"