Add dependabot automerge workflow

.github/workflows/dependabot-automerge.yml

@@ -0,0 +1,33 @@
+name: Auto-merge Dependabot PRs
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  dependabot:
+    runs-on: ubuntu-latest
+    if: github.actor == 'dependabot[bot]'
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Approve PR
+        run: |
+          gh pr review --approve "${{ github.event.pull_request.number }}"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Enable auto-merge
+        run: |
+          gh pr merge \
+            --squash \
+            --auto \
+            "${{ github.event.pull_request.number }}"
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}