ci: merge Dependabot pull requests automatically when tests pass (#579)

Author: mikavilpas

.github/workflows/test.yml

@@ -60,3 +60,16 @@ jobs:
           name: cypress-screenshots
           path: integration-tests/cypress/screenshots
           if-no-files-found: ignore # 'warn' or 'error' are also available, defaults to `warn`
+
+  automerge:
+    needs: build
+    name: Automerge Dependabot PRs
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+      contents: write
+    steps:
+      - uses: fastify/github-action-merge-dependabot@v3
+        with:
+          # https://github.com/fastify/github-action-merge-dependabot?tab=readme-ov-file
+          github-token: ${{ secrets.GITHUB_TOKEN }}