ci: add merge_group trigger for required ci / ci (#36)

.github/workflows/ci.yaml

@@ -20,6 +20,7 @@ on:
   pull_request:
   push:
     branches: [main]
+  merge_group:
 
 permissions:
   contents: read
@@ -31,7 +32,7 @@ jobs:
     timeout-minutes: 10
     concurrency:
       group: ci-${{ github.workflow }}-${{ github.ref }}
-      cancel-in-progress: true
+      cancel-in-progress: ${{ github.event_name == 'pull_request' }}
     steps:
       - uses: actions/checkout@v7