ci: enable auto-merge for Dependabot PRs

.github/workflows/deps-automerge.yml

@@ -0,0 +1,36 @@
+name: deps-automerge
+
+on:
+  pull_request:
+    branches:
+      - main
+
+permissions:
+  contents: write
+  pull-requests: write
+
+defaults:
+  run:
+    # NOTE: Default option does not include `-o pipefail` as documented
+    # unless explicitly specifying the `bash` shell.
+    # https://github.com/actions/runner/issues/353
+    shell: bash
+
+jobs:
+  automerge:
+    runs-on: ubuntu-22.04
+    timeout-minutes: 2
+    if: ${{ github.event.pull_request.user.login == 'dependabot[bot]' && github.repository_owner == 'loozhengyuan' }}
+
+    steps:
+      - name: Fetch Dependabot metadata
+        uses: dependabot/fetch-metadata@v2.2.0
+        with:
+          github-token: "${{ secrets.GITHUB_TOKEN }}"
+
+      - name: Enable auto-merge for Dependabot PRs
+        env:
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          PR_URL: ${{ github.event.pull_request.html_url }}
+        run: |
+          gh pr merge --auto --squash --delete-branch "${PR_URL}"