chore: when approving images, first pull that image

"tag and push" stage of "merge to staging" jobs are run on a separate VM than the one that built the candidate image, so we need to pull that image before retagging it.

Author: Shesekino

scripts/approve-image.sh

@@ -9,6 +9,7 @@ else
   IMAGE_NAME_CANDIDATE=snyk/kubernetes-monitor:staging-candidate
   IMAGE_NAME_APPROVED=snyk/kubernetes-monitor:${1}-approved
 
+  docker pull ${IMAGE_NAME_CANDIDATE}
   docker tag ${IMAGE_NAME_CANDIDATE} ${IMAGE_NAME_APPROVED}
   docker push ${IMAGE_NAME_APPROVED}
   ./scripts/slack-notify-push.sh ${IMAGE_NAME_APPROVED}