Create pull request comment when preview available

[vipulgupta2048]

To gain parity with GitHub actions on Handbook, we need to add a preview URL message to PR similar to balenaltd/handbook#52 (comment)

From: https://github.com/balenaltd/handbook/blob/main/.github/actions/publish/action.yml

    - name: Create pull request comment
      uses: marocchino/sticky-pull-request-comment@v2
      with:
        header: gh-preview
        GITHUB_TOKEN: ${{ fromJSON(inputs.secrets).FLOWZONE_TOKEN }}
        message: |
          :rocket: Deployed ${{ github.repository }}@${{ github.event.pull_request.head.sha }} to ${{ env.published_url }}

Also, investigate

• Does Cloudflare have a limit on previews being created? Or are they going to be unlimited? If it is the latter then we won't need a way to clean our old GitHub previews.

[maggie44]

For reference, I am not sure the preview URL in that PR you reference is working. It looks like it is building the docs without the changes in the PR. Maybe something we can explore for this new docs builder rather than digging around in the code which is going to be deprecated.

[vipulgupta2048]

I referenced only the feature, we do need to build out our own implementation. Cloudflare Pages creates a unique URL every single time so we are covered on that point.

Good thing you told me @Maggie0002 This will unblock the PR I have pending for the handbook to convert with Docusarus builder.

[anujdeshpande]

@vipulgupta2048 I think it might be a good idea in general to get some outputs from different flowzone steps in

• PR comments
• Summary of the action run

[klutchell]

An example of this being done for the handbook is here:
https://github.com/balenaltd/handbook/tree/50b6c0d9fef1a2a45138fb6869fa8e61103dec5e/.github/actions