Add GitHub Actions workflow for Docathon label sync

Author: nil-is-all

.github/workflows/docathon-sync-label.yml

@@ -0,0 +1,31 @@
+name: Docathon Labels Sync
+
+on:
+  pull_request_target:
+    types: [opened, synchronize, edited]
+    branches: [main]
+
+jobs:
+  check-labels:
+    if: github.repository_owner == 'pytorch'
+    runs-on: ubuntu-latest
+    permissions:
+      issues: write
+      pull-requests: write
+    steps:
+      - name: Check out the repo
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          fetch-depth: 1
+      - name: Set up Python
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5.6.0
+        with:
+          python-version: 3.x
+      - name: Install dependencies
+        run: |
+          pip install requests==2.32.3
+          pip install PyGithub==2.3.0
+      - name: Run Python script
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: python ./.github/scripts/docathon-label-sync.py ${{ github.event.pull_request.number }}