Updated PR workflow

Author: Zozman

.github/workflows/pr.yaml

@@ -4,6 +4,10 @@ on:
   pull_request:
     branches: [ main ]
 
+concurrency:
+  group: pr-validation-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
 jobs:
   test:
     name: Run Tests