message: ci: fix regression in docker push.
  I think this snafu came from moving to an array in
diff: @@ -41,7 +41,7 @@ fi
  docker login -u "$DOCKERHUB_USERNAME" -p "$DOCKERHUB_PASSWORD"
  -for BUILD_TYPE in ${BUILD_TYPES}; do
  +for BUILD_TYPE in "${BUILD_TYPES[@]}"; do
  docker tag "${DOCKER_IMAGE_PREFIX}${BUILD_TYPE}:local" "${DOCKER_IMAGE_PREFIX}${BUILD_TYPE}${IMAGE_POSTFIX}:${IMAGE_NAME}"
  docker push "${DOCKER_IMAGE_PREFIX}${BUILD_TYPE}${IMAGE_POSTFIX}:${IMAGE_NAME}"
  