chore: ensure concurrency on branch name

Author: SgtPooki

.github/workflows/ci.yml

@@ -7,6 +7,10 @@ on:
   pull_request:
     branches: [master]
 
+concurrency:
+  group: ${{ github.head_ref || github.ref_name }}
+  cancel-in-progress: true
+
 jobs:
   examples:
     runs-on: ubuntu-latest