change source of upload-artifact action

.github/workflows/docs.yml

@@ -14,6 +14,6 @@ jobs:
             - uses: cachix/install-nix-action@v27
             - name: Build package from flake
               run: nix build .#docs
-            - uses: actions/upload-artifact@v7
+            - uses: https://gitea.com/actions/gitea-upload-artifact@v4
               with:
                 path: ./result