Personal Access Token authentication isn't supported

[sudoforge]

It looks like #504 should have added this to v4, yet grabbing that version of the library from gopkg.in/src-d/go-git.v4 doesn't seem to contain the merge commit, c17627c. What's going on here? Do we need to have the changes made in the pull request re-submitted?

[orirawlings]

@bddenhartog I think this was noticed some time back in #535. Although I'm having trouble verifying now that changes was reintegrated to the proper branch.

@mcuadros, do you remember how the changes for #504 were finally integrated?

[sudoforge]

@orirawlings It doesn't look like token based authentication is supported in the current source, as far as I can tell. If it is supported, it's certainly not clear - perhaps this issue should be updated to reflect that and instead posit the addition of documentation detailing how to utilize token-based authentication (which should be a much better choice for someone using the library in an automated fashion...)

[mcuadros]

@bddenhartog far as I know to use GitHub token you can use BasicAuth with now user (or any string) and the token as the password.