gh-actions: add maintainer-list workflow

.github/workflows/maintainer-list.yml

@@ -0,0 +1,29 @@
+name: maintainer-list
+
+permissions: read-all
+
+on:
+  push:
+    branches:
+      - testing-maintainer-list
+
+jobs:
+  maintainer-list:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@main
+    - name: Set up Python 3.12
+      uses: actions/setup-python@v5
+      with:
+        python-version: 3.12
+    - name: Install Python dependencies
+      run: |
+        python -m pip install --upgrade pip
+        python -m pip install -r dist/tools/maintainer-list/requirements.txt
+    - name: Update doc/doxygen/src/maintainers.md
+      env:
+        GITHUB_TOKEN: ${{ secrets.RIOT_CI_ACCESS_TOKEN }}
+      run: |
+        ./dist/tools/maintainer-list/maintainer-list.py
+    - name: Check maintainers.md
+      run: cat doc/doxygen/src/maintainers.md