message: ci: fix typo with GITHUB_SHA
diff: @@ -76,12 +76,11 @@ jobs:
  run: |
  if [ $CUSTOM_IMAGE_NAME == '' ]
  then
  - echo "::set-output name=canary-docker-tag::$GITHUB_SHA_PREFIX"
  + echo "::set-output name=canary-docker-tag::${GITHUB_SHA::8}"
  else
  echo "::set-output name=canary-docker-tag::prerelease-$CUSTOM_IMAGE_NAME"
  fi
  env:
  - GITHUB_SHA_PREFIX: ${{ GITHUB_SHA::8 }}
  CUSTOM_IMAGE_NAME: ${{ github.event.inputs.customImageName }}
  