Automating Dependabot with GitHub Actions

Signed-off-by: utam0k <k0ma@utam0k.jp>

.github/workflows/dependabot_auto.yaml

@@ -0,0 +1,42 @@
+name: Dependabot automation
+
+on:
+  pull_request:
+    types:
+      - opened
+
+permissions:
+  pull-requests: write
+  contents: write
+  repository-projects: write
+
+jobs:
+  dependabot-automation:
+    runs-on: ubuntu-latest
+    if: ${{ github.actor == 'dependabot[bot]' }}
+    steps:
+      - name: Dependabot metadata
+        id: metadata
+        uses: dependabot/fetch-metadata@v1.3.5
+        with:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Approve & enable auto-merge for Dependabot PR
+        if: |
+          steps.metadata.outputs.update-type == 'version-update:semver-patch'
+        run: |
+          gh pr review --approve "$PR_URL"
+          gh pr edit "$PR_URL" -t "(auto merged) $PR_TITLE"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          PR_TITLE: ${{ github.event.pull_request.title }}
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Automerge
+        id: automerge
+        uses: pascalgn/automerge-action@v0.15.5
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          MERGE_LABELS: dependencies
+          MERGE_REQUIRED_APPROVALS: 1
+          MERGE_RETRY_SLEEP: 120000
+          MERGE_DELETE_BRANCH: true
+          MERGE_FILTER_AUTHOR: dependabot[bot]