Created by: mdogadailo
If user under proxy and didn't set HTTP_PROXY variable, create-react-app decides that user is offline and try to download packages from mirror, which are not here because you never download them (packages) before.
This patch adds getProxy function, that checks process.env.https_proxy and if it's undefined, will try to get https-proxy settings from Yarn (actually from npm) config file (.npmrc), if it's not defined yet, well we tried our best or you are offline.