CI: Support merge queues with default runner

Author: Repiteo

.github/workflows/runner.yml

@@ -1,5 +1,5 @@
 name: 🔗 GHA
-on: [push, pull_request]
+on: [push, pull_request, merge_group]
 
 concurrency:
   group: ci-${{ github.actor }}-${{ github.head_ref || github.run_number }}-${{ github.ref }}-runner