From Steven Abadie:
Git for Open Hardware Projects
Git has become the predominant version control software in Free and Open Source Software projects and communities. Git is excellent for tracking and managing changes to computer files and is especially powerful in managing source code. Although not as common, Git is also a worthy tool for managing the source of your hardware projects. It provides a clear time line of changes, log of contributors, and a system of synchronous development.
An additional advantage of using Git for Open Hardware are the available hosting options. All basic Git hosting services and software will provide a remote centralized git repository for your team or collaborators to sync to. Other common features you will find are issue tracking, project documentation, and team permission management. The three most common Git hosting services are Github, GitLab, and Bitbucket. If you prefer a self-hosted FOSS Git host, Gitea and Phabricator are great options.