New GitHub workflow to auto-update list of contributors

.github/workflows/auto-update-list-contributors.yml

@@ -0,0 +1,74 @@
+# GitHub Actions documentation:
+# https://docs.github.com/en/actions
+
+name: Auto-update list of contributors
+
+on:
+  workflow_call:
+
+    # https://github.com/akhilmhdh/contributors-readme-action#optional-parameters
+    inputs:
+      use_username:
+        description: If people should be listed with their username instead of their full name.
+        default: true
+        required: false
+        type: boolean
+
+jobs:
+  update_contributors:
+    runs-on: ubuntu-latest
+    timeout-minutes: 20
+    steps:
+
+      # https://github.com/akhilmhdh/contributors-readme-action
+      - name: Update the list of contributors in the README file
+        uses: akhilmhdh/[email protected]
+        id: update_contributors
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          commit_message: 'chore: auto-update contributors list (GH Action)'
+          committer_username: 'akhilmhdh/contributors-readme-action'
+          pr_title_on_protected: Auto-update list of contributors
+          use_username: ${{ inputs.use_username }}
+
+      # The previous step might have created a PR to make the update.
+      # If that's the case, we want to close any previous similar PR, to avoid duplication.
+      - name: 'Close previous pull request (if it exists)'
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          request="$( \
+            gh api search/issues \
+              --method GET \
+              --raw-field q='\
+                repo:${{ github.repository }} \
+                type:pr \
+                state:open \
+                sort:updated-asc \
+                author:app/github-actions \
+                "Auto-update list of contributors" in:title\
+              ' \
+          )"
+
+          count_pr=$( jq '.total_count' <<< $request )
+
+          # We are supposed to have either 1 or 2 PRs:
+          # - One PR:  1 created by the previous step + no existing PR
+          # - Two PRs: 1 created by the previous step + 1 existing PR
+          if [ $count_pr -eq 2 ]; then
+
+            # PRs are sorted by least recently updated date => the first is the oldest.
+            id_pr_oldest=$( jq '.items[0].number' <<< $request )
+
+            # Comment the oldest PR with a link to the new PR.
+            gh pr comment $id_pr_oldest \
+              --repo ${{ github.repository }} \
+              --body "Replaced by #${{ steps.update_contributors.outputs.pr_id }} ."
+
+            # And finally, close the PR.
+            gh pr close $id_pr_oldest \
+              --repo ${{ github.repository }} \
+              --delete-branch
+
+          fi