fix: use the correct protocol via http_proxy
fix: use the correct protocol via http_proxy

Pass a protocol to caw. Before this change, always HTTP was passed
even when HTTPS was needed.

fix #322

pnpm/pnpm,andreypopp/pnpm,pnpm/supi,rstacruz/pnpm,pnpm/supi,rstacruz/pnpm,pnpm/pnpm,pnpm/supi,pnpm/pnpm,rstacruz/pnpm,andreypopp/pnpm,andreypopp/pnpm