Replace changelog entries generation script
Same change as gitlab-org/gitlab-runner!1888 (merged).
This MR will need to be synced with gitlab-org/ci-cd/runner-release-helper!20 (merged), which will change the https://gitlab.com/gitlab-org/ci-cd/runner-release-helper's template that contains step for the changelog entries generation.
Edited by Tomasz Maczukin