How do I update github actions to Node.js 20?

I’m dealing with the same problem, and not getting anywhere. I have to confess to having no understanding of GitHub actions. I thought I could maybe solve my problem by specifying node-version [20], but clearly I’m wrong. Can anyone help? These lines are in CI.yml:

jobs:
  test:
    name: Julia ${{ matrix.version }} - ${{ matrix.os }} - ${{ matrix.arch }} - ${{ github.event_name }}
    runs-on: ${{ matrix.os }}
    strategy:
      fail-fast: false
      matrix:
        node-version: [20]
        version:
          - '1'
          - 'nightly'
        os:
          - ubuntu-latest
        arch:
          - x64
    steps:
      - uses: actions/checkout@v4
      - uses: julia-actions/setup-julia@v1
        with:
          version: ${{ matrix.version }}
          arch: ${{ matrix.arch }}
      - uses: julia-actions/cache@v1
      - uses: julia-actions/julia-buildpkg@v1
      - uses: julia-actions/julia-runtest@v1