message: ci: look for 'Closes' on last line of commit message
diff: @@ -595,7 +595,7 @@ jobs:
  name: should pre build docker images (targeting a release branch)?
  command: |
  export commit_message=$( git log -1 --pretty=%B )
  - export pr_num=`echo "$commit_message" | tail -2 | head -1 | sed 's/Closes: #//'`
  + export pr_num=`echo "$commit_message" | tail -1 | sed 's/Closes: #//'`
  if [ -z $pr_num ]; then
  echo "Did not find pull request num in commit message. -\\_(O_o)_/-";
  exit 1
  