ci: add Dependabot auto-merge workflow for patch and minor bumps

Author: ph33nx

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

@@ -0,0 +1,28 @@
+name: Dependabot auto-merge
+
+on: pull_request
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  auto-merge:
+    if: github.actor == 'dependabot[bot]'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Fetch Dependabot metadata
+        id: meta
+        uses: dependabot/fetch-metadata@v2
+      - name: Auto-approve patch and minor bumps
+        if: steps.meta.outputs.update-type == 'version-update:semver-patch' || steps.meta.outputs.update-type == 'version-update:semver-minor'
+        run: gh pr review --approve "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Enable auto-merge for patch and minor bumps
+        if: steps.meta.outputs.update-type == 'version-update:semver-patch' || steps.meta.outputs.update-type == 'version-update:semver-minor'
+        run: gh pr merge --auto --squash --delete-branch "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}