Switched pr_number for branch when downlading artifacts

Author: rfoyard

.github/workflows/build-and-release.yml

@@ -18,7 +18,7 @@ jobs:
         uses: dawidd6/action-download-artifact@v2
         with:
           workflow: test-and-train.yml
-          pr: ${{github.event.pull_request.number}}
+          branch: ${{github.head_ref}}
           name: models
           path: models
       - name: 'Checkout'