@nakajmg, if you are building the site in some other CD/CI system, you can actually deploy the build files directly from that system using our CLI tools.
netlify deploy or
netlify deploy --prod allows for manual updating of a site from the command line. This command can be added to your build scripts to deploy from the locally or CD/CI built site.
Does that solution meet your requirements?
If so, we also need to unlink the repository from the Netlify site and, at this time, we must do that for you here in support (because the UI doesn’t have an “unlink git repo” option at this time).
If you want us to unlink the repo from the site (because you will be using this manual deploy solution) please let us know and we’ll be happy to do so.