Update validation.yml

.github/workflows/validation.yml

@@ -42,7 +42,7 @@ jobs:
               if: github.event_name == 'pull_request'
               id: files
               run: |
-                  echo "changed_files=$(git diff --name-only -r HEAD^1 HEAD | xargs)" >> $GITHUB_OUTPUT
+                  echo "changed_files=$(git diff --name-only HEAD~1 HEAD | xargs)" >> $GITHUB_OUTPUT
                   echo $changed_files
 
             - run: npm test