Allow --no-single-branch git option (dupe of #4806)

[drd]

Overview

It is useful to be able to compare across branches for certain CI-related tasks. With current versions of git, cloning using the --depth flag also automatically enables the --single-branch option, causing git to fetch only the specified branch for the commit travis is building. As pointed out in #4806, there are ways around this, but they have a significant performance penalty: running git fetch --unshallow retrieves the entire commit history, which for many projects, is an undue burden.

Request

Please allow an option to specify --no-single-branch in the travis config. 🙏

[stale]

Thanks for contributing to this issue. As it has been 90 days since the last activity, we are automatically closing the issue in 7 days. This is often because the request was already solved in some way and it just wasn't updated or it's no longer applicable. If that's not the case, please respond before the issue is closed, or open a new one after. We'll gladly take a look again! You can read more here: https://blog.travis-ci.com/2018-03-09-closing-old-issues

[widyhafiz03]

Good job, good first issue