Correct me if I'm wrong

Updated on Dec. 3rd 2017. Having recently started to use GitLab and their automated pipelines (GitLab CI) for hosting this website on GitLab Pages, I wanted to also learn how I can use their service to upload artifacts to S3. There are tutorials out there that do a good job in explaining how to do it and in more detail (e.g this or this), but I think that my solution has some valuable ideas points too.