Add baseline

Author: devknoll

.github/workflows/build_test.yml

@@ -43,3 +43,16 @@ jobs:
           ./wpt/wpt manifest
           ./wpt/wpt serve --inject-script=${{ github.workspace }}/dist/container-query-polyfill.modern.js &
           npm test
+
+      - name: Open Pull Request
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          node --loader ts-node/esm ./tests/diff.ts
+          git config user.name github-actions[bot]
+          git config user.email 41898282+github-actions[bot]@users.noreply.github.com
+          git checkout -b update-wpt-baseline-${{ github.job_id }}
+          git add ./tests/baseline.json
+          git commit -m "Update Web Platform Test baseline"
+          git push -u origin HEAD
+          gh pr create --title "[Automated] Update Web Platform Tests" --body-file ./tests/pr.txt