fix origin from external

Author: greole

.github/workflows/trigger-lrz-gitlab-ci.yaml

@@ -89,9 +89,10 @@ jobs:
           git config user.name "github-actions[bot]"
           git config user.email "github-actions[bot]@users.noreply.github.com"
           git remote add lrz https://oauth2:${PYGINKGO_PROJECT_TOKEN}@${{ env.LRZ_HOST }}/${{ env.LRZ_GROUP }}/${{ env.REPO_NAME }}.git
-          git fetch origin ${{ steps.branch.outputs.branch }}
-          git checkout -B ${{ steps.branch.outputs.branch }} origin/${{ steps.branch.outputs.branch }}
-          git reset --hard origin/${{ steps.branch.outputs.branch }}
+          git remote add incoming ${{ github.event.pull_request.head.repo.clone_url }}
+          git fetch incoming  ${{ steps.branch.outputs.branch }}
+          git checkout -B ${{ steps.branch.outputs.branch }} incoming/${{ steps.branch.outputs.branch }}
+          git reset --hard incoming/${{ steps.branch.outputs.branch }}
           git push --force lrz HEAD:refs/heads/${{ steps.branch.outputs.branch }}
 
       - name: Cancel running/pending pyGinkgo LRZ CI pipelines