Add a comment to the PR triggered Benchmark workflow

[skyleaworlder]

PR Checklist

• Tests are added
• Documentation, if applicable

Description

I'll temporarily NOT merge this PR, for I need some time to validate its feasibility.

In this PR, I introduced two new inputs, repository and pr_id, which are both the parameters of peter-evans/create-or-update-comment.

The new comment here is also posted by GitHub Actions.

And it was added by this run:

jobs:
  benchmark:
    runs-on: ubuntu-latest
    steps:
      -
        run: |
          echo "# Hello World!" > report.md
      -
        name: Upload report
        uses: actions/upload-artifact@v2
        with:
          name: report.md
          path: report.md
  Comment:
    needs: [benchmark]
    runs-on: ubuntu-latest
    steps:
      -
        name: Download report
        uses: actions/download-artifact@v3
        with:
          name: report.md
      -
        name: Comment
        uses: peter-evans/create-or-update-comment@v2
        with:
          issue-number: ${{ github.event.inputs.pr_id }}
          repository: ${{ github.event.inputs.repository }}
          token: ${{ secrets.PAT }}
          body-file: report.md

[skyleaworlder]

This feature requires a PAT (Personal Access Token) generated by a maintainer, and this PAT requires at least "read and write" access to "pull_request", which means the "comment" action can access all the objects (e.g. labels, assignees, especially comments) and then add a new comment to the target PR.

[skyleaworlder]

Merge this for new PRs.