If you merge PRs from GitHub bots do you own full repo copyright?

I basically automatically merge "security" and "dependency" updates from GitHub. Until today I never thought about the copyright implications. I want to maintain copyright ownership of my repos, so do I need a copyright assignment from GitHub? I think it's an interesting issue, because if you accept a contribution from a human author, they obviously have a copyright claim over your repo...but what's the situation with these bot commits from GitHub? Does GitHub have some control over my work in a copyright sense now, in that if I want to sell license exemptions for corporates, or sell ownership of the repo, do I need to get some sort of release, or assignment or permission from GitHub?