Update jscpd.yml (prebid#11793)

.github/workflows/jscpd.yml

@@ -14,6 +14,7 @@ jobs:
       uses: actions/checkout@v4
       with:
         fetch-depth: 0  # Fetch all history for all branches
+        ref: ${{ github.event.pull_request.head.sha }}
 
     - name: Set up Node.js
       uses: actions/setup-node@v4