CI job for releasing the chart
Closes: https://gitlab.com/charts/gitlab/issues/484
Currently relies on the build trigger user, and an access token in order to push. Token is protected so only available to protected branches.
@marin if we add a new release bot user and give them a private ssh key, we can use https://gitlab.com/gitlab-org/release-tools/blob/master/scripts/setup_ssh.sh instead (with the private key needing to sit in a protected ci secret)
Example of a dry-run: https://gitlab.com/gitlab-org/build/CNG/-/jobs/76648488
Edited by DJ Mountney