Add dummy DCO job for the merge queue

The DCO GitHub app doesn't support merge queues yet, so to be able to
make DCO a required check for PRs, we need to provide a dummy DCO check
that will always pass for merge queues actions (if a PR is in the merge
we already know the DCO check passed anyway).

Note that we include the whole workflow in a jinja raw block to avoid
clashed between GitHub variable replacement and jinja variable
replacement, which overlap.

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

cookiecutter/{{cookiecutter.github_repo_name}}/.github/workflows/dco-merge-queue.yml

@@ -0,0 +1,13 @@
+{% raw -%}
+# Based on https://github.com/hyperledger/besu/pull/5207/files
+name: DCO
+on:
+  merge_group:
+
+jobs:
+  DCO:
+    runs-on: ubuntu-latest
+    if: ${{ github.actor != 'dependabot[bot]' }}
+    steps:
+      - run: echo "This DCO job runs on merge_queue event and doesn't check PR contents"
+{%- endraw %}