Allow pushing to either main branch or master branch

[DerekRobin]

Currently the github API call is hardcoded to push to main, it would be nice to push to either main or master based on the repo you select

[keanelekenns]

There must be a very simple way to do this. origin/HEAD should point to whatever the main/master branch is, so I think we could just use that (assuming I have that right).

[DerekRobin]

githubapi/getHead.ts has the branch hardcoded as main, this is the reason for only being able to push to main right now. In the future we will have an option to push to main/master branch or a new branch.