Merge branch 'jy-add-rollout-to-gitlab-feature-group-in-template' into 'master'

Updates to feature flag rollout template

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/159012



Merged-by: Dylan Griffith <dyl.griffith@gmail.com>
Approved-by: Dylan Griffith <dyl.griffith@gmail.com>
Co-authored-by: Jessie Young <jessieyoung@gitlab.com>