[build] Bump actions/upload-artifact in generate-gh-pages: v1->v4

Author: AndreyAkinshin

.github/workflows/generate-gh-pages.yaml

@@ -31,7 +31,7 @@ jobs:
       run: ./build.cmd docs-build
 
     - name: Upload Artifacts
-      uses: actions/upload-artifact@v1
+      uses: actions/upload-artifact@v4
       with:
         name: site
         path: docs/_site