fix generated image name and tag (#122)

Signed-off-by: Mohamed Mahmoud <mmahmoud@redhat.com>

.github/workflows/push_image_pr.yml

@@ -48,5 +48,5 @@ jobs:
               issue_number: context.issue.number,
               owner: context.repo.owner,
               repo: context.repo.repo,
-              body: 'New image: ${{ steps.push-to-quay.outputs.registry-paths }}. It will expire after two weeks.'
+              body: 'New image: ${{ env.REGISTRY }}/${{ env.IMAGE }}:${{ env.short_sha }}. It will expire after two weeks.'
             })