workflow: updated version

Author: gxben

.github/workflows/hugo.yaml

@@ -82,7 +82,7 @@ jobs:
         with:
           config: .htmltest.yml
       - name: Archive htmltest results
-        uses: actions/upload-artifact@v2
+        uses: actions/upload-artifact@v4
         with:
           name: htmltest-report
           path: tmp/.htmltest/htmltest.log