Add formatting workflow (#1770)

Co-authored-by: Thomas Weber <[email protected]>

.github/workflows/format-pr.yml

@@ -0,0 +1,43 @@
+name: Format pull request
+
+on:
+  workflow_dispatch:
+  issue_comment:
+    types: [created]
+
+jobs:
+  format:
+    runs-on: ubuntu-latest
+
+    if: |
+      github.event_name == 'workflow_dispatch' || (
+        github.event_name == 'issue_comment' &&
+        github.event.issue.pull_request &&
+        contains(github.event.comment.body, '!format')
+      )
+
+    permissions:
+      contents: write
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683
+        with:
+          # Credentials needed for pushing changes at the end
+          persist-credentials: true
+      - name: Install Node.js
+        uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af
+        with:
+          node-version: 20.x
+      - name: Install dependencies
+        run: npm ci
+      - name: Format
+        run: npm run format
+      - name: Commit
+        run: |
+          git config --global user.name "$GITHUB_ACTOR"
+          git config --global user.email "[email protected]"
+          git stage .
+          git commit --author "format-pr-bot <[email protected]>" -m "[Automated] Format code" || echo "No changes to commit"
+      - name: Push
+        run: git push