parse json and export output in github actions

meta.yaml

jobs:
  job:
    steps:
      - name: Docker meta
        id: meta
        uses: docker/metadata-action@v4
        with:
          images: my/image
      - id: version
        run: |
          echo "::set-output name=value::${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.version'] }}"