add auto merge to dpbot

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

@@ -0,0 +1,34 @@
+# Based on https://docs.github.com/en/code-security/supply-chain-security/keeping-your-dependencies-updated-automatically/automating-dependabot-with-github-actions#enable-auto-merge-on-a-pull-request
+name: Dependabot auto-merge
+on: pull_request_target
+
+permissions:
+    pull-requests: write
+    contents: write
+
+jobs:
+    dependabot:
+        runs-on: ubuntu-latest
+        if: ${{ github.actor == 'dependabot[bot]' }}
+        steps:
+            - name: Dependabot metadata
+              id: metadata
+              uses: dependabot/fetch-metadata@v1.3.1
+              with:
+                  github-token: "${{ secrets.GITHUB_TOKEN }}"
+
+            - name: Enable auto-merge for Dependabot PRs
+              # Automatically merge semver-patch and semver-minor PRs
+              # or black dependency upgrades
+              if: "${{ steps.metadata.outputs.update-type ==
+                  'version-update:semver-minor' ||
+                  steps.metadata.outputs.update-type ==
+                  'version-update:semver-patch' ||
+                  steps.metadata.outputs.dependency-names ==
+                  'black' }}"
+
+              # https://cli.github.com/manual/gh_pr_merge
+              run: gh pr merge --auto --squash "$PR_URL"
+              env:
+                  PR_URL: ${{github.event.pull_request.html_url}}
+                  GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}