we are developing a tool that can use various git offerings as a backend - GitHub, GitLab and Bitbucket. The tool uses theses servers APIs to create groups and repos. We’d like to continously test our integration with the GitHub API without actually having to buy our own GitHub license (as we are using GitLab internally). Is there any developer instance of GitHub Enterprise available to allow for tests like these? Or is the only way to buy a minimum number of seats and run our own instance?