Use https to make it work via http proxies in a coporate environment

Hi there,

I kindly ask to switch from `git`-protocol to `https` when using the `github`-source-option. This would make the life of users easier, if there is a http-proxy in use.

I know that there's the possibility to use a git proxy + `socat`, but that needs to be configured and supported on every developer machine while using http(s) as transport-protocol works out of the box.

Thank you very much.

Cheers,
dg