Updated upload-pages-artifact to v4

Author: marcosfrenkel

.github/workflows/documentation.yml

@@ -36,7 +36,7 @@ jobs:
         run: make html
 
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v2
+        uses: actions/upload-pages-artifact@v4
         with:
           path: 'build/html'