Remix release v0.18.0 now includes full support for a plugin called dGIT that allows you to interact with GitHub as if you were doing it on your terminal or in VSCode.

It supports cloning, pushing ( with pushing with force), pulling, using branches, working with remotes & checking out previous commits & files. It also includes a nifty diff viewer.

The app does not handle more advanced tasks such as rebasing, squashing and the like. But you should find the basics to be ample.