message: ci: fix build image push
diff: #!/bin/bash
  [[ -z "${LINUX_DISTRO}" ]] && LINUX_DISTRO="ubuntu"
  -[[ -z "${IMAGE_NAME}" ]] && IMAGE_NAME=lyft/envoy-build-"${LINUX_DISTRO}"
  +[[ -z "${IMAGE_NAME}" ]] && IMAGE_NAME=envoyproxy/envoy-build-"${LINUX_DISTRO}"
  # We need //bazel/... and WORKSPACE for the build, but it's not in ci/build_container. Using Docker
  # relative path workaround from https://github.com/docker/docker/issues/2745#issuecomment-253230025
  