Enable Dependabot Auto-Merge on Main

Closes gh-18712

Signed-off-by: Josh Cummings <3627351+jzheaux@users.noreply.github.com>

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

@@ -0,0 +1,25 @@
+name: Dependabot Auto-Merge
+on:
+  pull_request:
+    branches:
+      - 'main'
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  dependabot:
+    runs-on: ubuntu-latest
+    if: github.event.pull_request.user.login == 'dependabot[bot]' && github.repository == 'spring-projects/spring-security'
+    steps:
+      - name: Dependabot metadata
+        id: metadata
+        uses: dependabot/fetch-metadata@d7267f607e9d3fb96fc2fbe83e0af444713e90b7
+        with:
+          github-token: ${{ github.token }}
+      - name: Enable auto-merge for Dependabot PRs
+        run: gh pr merge --auto --merge "$PR_URL"
+        env:
+          PR_URL: ${{ github.event.pull_request.html_url }}
+          GH_TOKEN: ${{ github.token }}