Set WHEY_TRACEBACK for Build step of smoke test

.github/workflows/smoke_test.yml

@@ -113,6 +113,7 @@ jobs:
       - name: Build
         run: |
           python3 -m virtualenv venv
+          WHEY_TRACEBACK = 1
           python3 -m pip install $(pyproject-parser info build-system.requires -f /tmp/${{ matrix.config.name }}/pyproject.toml | jq 'join(" ")' -r) --prefix venv -I
           python3 -m pip install /tmp/${{ matrix.config.name }} --prefix venv -I --no-build-isolation
           venv/bin/python -m pip install -r /tmp/${{ matrix.config.name }}/tests/requirements.txt ${{ matrix.config.extra-install-args }} || exit 1