Add workflow for merging dependabot PR automatically

.github/workflows/vscode.yml

@@ -9,7 +9,7 @@ on:
       - master
 
 jobs:
-  build:
+  test:
     strategy:
       matrix:
         # TODO: support other platform such as macos
@@ -30,3 +30,23 @@ jobs:
     - run: gem install bundler
     - run: npm install
     - run: xvfb-run -a npm test
+
+  dependabot:
+    needs: test
+    runs-on: ubuntu-latest
+    if: ${{ github.event_name == 'pull_request' && github.actor == 'dependabot[bot]' }}
+    permissions:
+      contents: write
+      pull-requests: write
+    steps:
+      - name: Dependabot metadata
+        id: metadata
+        uses: dependabot/fetch-metadata@v1
+        with:
+          github-token: "${{ secrets.GITHUB_TOKEN }}"
+      - name: Enable auto-merge for Dependabot PRs
+        if: ${{ steps.metadata.outputs.update-type != 'version-update:semver-major' }}
+        run: gh pr merge --auto --merge "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}