ci: guide concurrency [ci skip]

Author: soyuka

.github/workflows/guides.yaml

@@ -4,6 +4,10 @@ on:
     push:
     pull_request:
 
+concurrency:
+  group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
+  cancel-in-progress: true
+
 env:
     COMPOSER_TOKEN: ${{ secrets.GITHUB_TOKEN }}
     COVERAGE: '0'