Only add gcr.io images to publish results

The release process generates and number of container images and
publishes them to gcr.io as well as three regional versions of the
registry. Today all those images are added to the IMAGES result,
for signing by chains, however that causes the nightly build to
fail as we hit the termination message size limit.

Until we have a way to store larger results, we shall only sign
images on gcr.io as a workaround.

Workaround to #4282

Signed-off-by: Andrea Frittoli <andrea.frittoli@uk.ibm.com>

tekton/publish.yaml

@@ -202,6 +202,8 @@ spec:
             TAG="$(params.versionTag)"
             crane cp ${IMAGE_WITH_SHA} ${REGION}.${IMAGE_WITHOUT_SHA_AND_TAG}:$TAG
           fi
-          echo ${REGION}.$IMAGE_WITH_SHA, >> $(results.IMAGES.path)
+          # Until we are able to store larger results, we cannot include the
+          # regional copies of the images in the result - see https://github.com/tektoncd/pipeline/issues/4282
+          # echo ${REGION}.$IMAGE_WITH_SHA, >> $(results.IMAGES.path)
         done
       done