add result output

[thattommyhall]

I am using this to do chat-ops with peter-evans/{slash-command-dispatch|create-or-update-comment}

      - name: Apply
        id: apply
        uses: ./.github/actions/octodns-sync
        env:
          DNSIMPLE_TOKEN:  ${{ secrets.DNSIMPLE_TOKEN }}
        with:
          config_path: config.yaml

      - name: Add reaction
        uses: peter-evans/create-or-update-comment@v1
        with:
          token: ${{ secrets.PAT }}
          repository: ${{ github.event.client_payload.github.payload.repository.full_name }}
          issue-number: ${{ github.event.client_payload.github.payload.issue.number }}
          body: |
            DID IT!

        ${{ steps.apply.outputs.result }}
        ```

[solvaholic]

In #24 I switched this to use screen rather than tee, and preserve the exit code.

@thattommyhall I'll mark this pull request closed. Please do re-open if the log file won't meet your needs or we've more to discuss.

Thank you 🙇