Prerelease branches (Branch where updates push releases to Github, not mods.Factorio.com)

[nicholasgower]

I'm currently managing a prerelease branch of one of my Factorio mods, and it would be helpful if there was a way to mark branches as "prerelease" branches. When a prerelease branch receives commits, it should follow the same semantic-release process, generating a changelog and incrementing the version number, but only uploading the resulting release to Github, not to the mod portal.

[fgardt]

I'm always open to PRs but I'm honestly not sure how well such a system could work for Factorio mods. Your prereleases would either keep increasing the version number every time or stay on the same version since there is no good way to mark such prerelease versions (like with -rc1 or something).