update action version

Author: andrewelamb

.github/workflows/test2.yaml

@@ -55,7 +55,7 @@ jobs:
       - uses: actions/setup-python@v4
         with:
           python-version: ${{ matrix.python }}
-      - uses: actions/download-artifact@v3
+      - uses: actions/download-artifact@v4
         with: { name: python-distribution-files, path: dist/ }
       - name: Install tox-gh plugin
         run: python -m pip install tox-gh>=1.2