[FEATURE] automatic checkout

[akostadinov]

Is your feature request related to a problem? Please describe.

I want to have a shorter workflow file and skip checkout step when all needed is to just checkout source from current event.

For example with buildx I can have:

...
      - name: Build and push Docker image
        id: build-and-push
        uses: docker/build-push-action@v2
        with:
          push: ${{ github.event_name != 'pull_request' }}
          tags: ${{ steps.meta.outputs.tags }}
          platforms: ${{ inputs.platforms }}
          labels: ${{ steps.meta.outputs.labels }}
          file: openshift/system/Dockerfile

With buildah I need to do:

- uses: actions/checkout@v3

- name: Build image
    id: build-image
    uses: redhat-actions/buildah-build@v2
    ...

Describe the solution you'd like

Checkout to happen automatically.