This doesn't make any sense to me. And I've written a Go reverse proxy server https://github.com/carlmjohnson/simple-reverse-proxy .

Python's SimpleHTTPServer is for when you have some directory on your computer and you want to test it locally in the browser. That's all. So, there's no reason to use GZIP or HTTP2 with a SimpleHTTPServer replacement. If you need those features, it's because you're doing things _in production_, in which case you should use Nginx, Apache, or Caddy (if you really want to use something Go-based).

TL;DR: If you need GZIP/HTTP2, it's not "simple."