pkg_tar tgz hashes change with Fedora 40 and zlib-ng

We are using `pkg_tar` to package helm charts into `tgz` files (helm only supports `.tgz`/`.tar.gz`). I recently upgraded my system to Fedora 40 and noticed all the chart hashes changing. Turns out [they switched from `zlib` to `zlib-ng`](https://fedoraproject.org/wiki/Changes/ZlibNGTransition), which is API compatible but changes the resulting archives with the same input.

Is there some way to work around this? As far as I can see `rules_pkg` is just using python gzip which makes use of the OS-specific zlib library installed. This makes reproducible builds across different systems quite difficult (e.g. some team members use MacOS).