Add auto approve for dependabot PRs (#8)

.github/workflows/auto-merge.yaml

@@ -0,0 +1,29 @@
+name: 'Dependabot auto-approve'
+
+on: pull_request
+
+jobs:
+  dependabot:
+    runs-on: ubuntu-latest
+    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' }}
+    steps:
+      - name: Dependabot metadata
+        id: dependabot-metadata
+        uses: dependabot/fetch-metadata@v1
+
+      - uses: actions/checkout@v4
+
+      - name: Setup gh cli
+        uses: ksivamuthu/actions-setup-gh-cli@v2
+
+      - name: Approve a Dependabot PR
+        run: gh pr review --approve "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+
+      - name: Enable auto-merge for Dependabot PRs
+        run: gh pr merge --auto --squash "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GH_TOKEN: ${{secrets.GITHUB_TOKEN}}