Add auto-merge on dependabot PR

.github/workflows/java8-maven.yml

@@ -4,7 +4,7 @@ on: [ push, pull_request ]
 
 jobs:
   build-and-test-job:
-    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.event.pull_request.base.repo.full_name
+    if: github.event_name == 'pull_request' || startsWith(github.ref, 'refs/heads/develop') || startsWith(github.ref, 'refs/tags/v')
     strategy:
       fail-fast: false
       matrix:
@@ -36,6 +36,23 @@ jobs:
         with:
           run: mvn -U -B -ntp package
 
+  auto-merge-job:
+    needs: build-and-test-job
+    if: startsWith(github.repository, 'nbbrd/') && github.event_name == 'pull_request' && github.actor == 'dependabot[bot]'
+    permissions:
+      contents: write
+      pull-requests: write
+
+    name: Auto-merge on dependabot PR
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Merge PR
+        run: gh pr merge --auto --rebase "$PR_URL"
+        env:
+          PR_URL: ${{github.event.pull_request.html_url}}
+          GITHUB_TOKEN: ${{secrets.GITHUB_TOKEN}}
+
   snapshot-job:
     needs: build-and-test-job
     if: startsWith(github.repository, 'nbbrd/') && startsWith(github.ref, 'refs/heads/develop')