add dependabot-auto-approve.yml

.github/workflows/dependabot-auto-approve.yml

@@ -0,0 +1,27 @@
+# by https://zenn.dev/nemuki/articles/dependabot-auto-merge
+name: Auto approve on dependabot PR at patch update
+
+on:
+  pull_request_target:
+    types:
+      - opened
+
+permissions:
+  pull-requests: write
+
+jobs:
+  dependabot-auto-approve:
+    runs-on: ubuntu-latest
+    if: ${{ github.actor == 'dependabot[bot]' }}
+    steps:
+      - name: Dependabot metadata
+        id: dependabot-metadata
+        uses: dependabot/fetch-metadata@v1
+        with:
+          github-token: '${{ secrets.GITHUB_TOKEN }}'
+      - name: Approve a PR
+        if: ${{ steps.dependabot-metadata.outputs.update-type == 'version-update:semver-patch' }}
+        run: gh pr review --approve "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}