Update pr-validation.yml

Author: rezmoss

.github/workflows/pr-validation.yml

@@ -1,7 +1,7 @@
 name: PR Validation
 
 on:
-  pull_request:
+  pull_request_target:
     types: [opened, edited, synchronize]
     paths:
       - 'README.md'
@@ -18,6 +18,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
         with:
+          ref: ${{ github.event.pull_request.head.sha }}
           fetch-depth: 0
 
       - name: Get changed files