Update build_downport.yaml (#341)

Author: oblomov-dev

.github/workflows/build_downport.yaml

@@ -22,7 +22,7 @@ jobs:
       uses: peaceiris/actions-gh-pages@v3
       if: github.ref == 'refs/heads/main' && github.repository == 'abap2UI5/abap2UI5-samples'
       with:
-        external_repository: abap2UI5-downports/samples
+        external_repository: abap2UI5-downports/abap2UI5-samples
         user_name: 'github-actions[bot]'
         user_email: 'github-actions[bot]@users.noreply.github.com'
         publish_branch: main