env is not passed to the install block

[umonaca]

Add a single line to the install block, then it will fail with error "artifact_name: parameter not set".

on: [push, pull_request]

jobs:
  build_job:
    # The host should always be linux
    runs-on: ubuntu-18.04
    name: Build on ${{ matrix.distro }} ${{ matrix.arch }}

    # Run steps on a matrix of 3 arch/distro combinations
    strategy:
      matrix:
        include:
          - arch: aarch64
            distro: ubuntu18.04
          - arch: ppc64le
            distro: alpine_latest
          - arch: s390x
            distro: fedora_latest

    steps:
      - uses: actions/checkout@v2.1.0
      - uses: uraimo/run-on-arch-action@v2.0.5
        name: Build artifact
        id: build
        with:
          arch: ${{ matrix.arch }}
          distro: ${{ matrix.distro }}

          # Not required, but speeds up builds
          githubToken: ${{ github.token }}

          # Create an artifacts directory
          setup: |
            mkdir -p "${PWD}/artifacts"

          # Mount the artifacts directory as /artifacts in the container
          dockerRunArgs: |
            --volume "${PWD}/artifacts:/artifacts"

          # Pass some environment variables to the container
          env: | # YAML, but pipe character is necessary
            artifact_name: git-${{ matrix.distro }}_${{ matrix.arch }}

          # The shell to run commands with in the container
          shell: /bin/sh

          # Install some dependencies in the container. This speeds up builds if
          # you are also using githubToken. Any dependencies installed here will
          # be part of the container image that gets cached, so subsequent
          # builds don't have to re-install them. The image layer is cached
          # publicly in your project's package repository, so it is vital that
          # no secrets are present in the container state or logs.
          install: |
            case "${{ matrix.distro }}" in
              ubuntu*|jessie|stretch|buster)
                apt-get update -q -y
                apt-get install -q -y git
                echo "${artifact_name}"
                ;;
              fedora*)
                dnf -y update
                dnf -y install git which
                ;;
              alpine*)
                apk update
                apk add git
                ;;
            esac

          # Produce a binary artifact and place it in the mounted volume
          run: |
            cp $(which git) "/artifacts/${artifact_name}"
            echo "Produced artifact at /artifacts/${artifact_name}"

      - name: Show the artifact
        # Items placed in /artifacts in the container will be in
        # ${PWD}/artifacts on the host.
        run: |
          ls -al "${PWD}/artifacts"

The line that I added is echo "${artifact_name}".