Backport PRs to stable branches workflow (cocotb/cocotb)

# Copyright cocotb contributors
# Licensed under the Revised BSD License, see LICENSE for details.
# SPDX-License-Identifier: BSD-3-Clause
 
# A workflow to automatically backport pull requests to a stable branch.
#
# This workflow uses the Backport CLI (https://github.com/sorenlouv/backport)
# under the hood, which is configured in `.backportrc.json` in the repository
# root.
#
# See https://github.com/sorenlouv/backport-github-action for documentation
# on the used action.
 
name: Backport PRs to stable branches
 
on:
  pull_request_target:
    # Run this workflow when a label on a PR is added, or if it's closed.
    types: ["labeled", "closed"]
 
jobs:
  backport:
    timeout-minutes: 30
    name: Backport PR
    if: github.event.pull_request.merged == true
    runs-on: latchkey-small
    steps:
      # Run the backport action only on PRs with one of the `backport-to:`
      # labels applied.
      #
      # Also update `branchLabelMapping` in `.backportrc.json` when changing the
      # label here.
      #
      # Implementation note: GitHub's contains() is matching the full string
      # when operating on an array (and startsWith() does not operate on arrays
      # at all). Do the label matching with jq instead.
      - name: Check for backport labels
        id: check_labels
        run: |-
          labels='${{ toJSON(github.event.pull_request.labels.*.name) }}'
          matched=$(echo $labels | jq '.|map(select(startswith("backport-to:"))) | length')
          echo "matched=$matched"
          echo "matched=$matched" >> $GITHUB_OUTPUT
 
      - name: Backport Action
        if: fromJSON(steps.check_labels.outputs.matched) > 0
        uses: sorenlouv/backport-github-action@8a6c0381851f43f9f1fddc7303f0e9015eb57b62  # v12.0.4
        with:
          # GITHUB_TOKEN is available by default, but the powers it has are
          # configurable. Follow the GitHub documentation at
          # https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/enabling-features-for-your-repository/managing-github-actions-settings-for-a-repository#setting-the-permissions-of-the-github_token-for-your-repository
          # to "Allow GitHub Actions to create and approve pull requests".
          github_token: ${{ secrets.GITHUB_TOKEN }}
 
      - name: Info log
        if: ${{ fromJSON(steps.check_labels.outputs.matched) > 0 && success() }}
        run: cat ~/.backport/backport.info.log
 
      - name: Debug log
        if: ${{ fromJSON(steps.check_labels.outputs.matched) > 0 && failure() }}
        run: cat ~/.backport/backport.debug.log