Merge branch '409875-add-utils-for-holt-winters-forecast' into 'master'

Add deployment frequency forecast utils

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/126996



Merged-by: Anna Vovchenko <avovchenko@gitlab.com>
Approved-by: Diana Zubova <dzubova@gitlab.com>
Approved-by: Anna Vovchenko <avovchenko@gitlab.com>
Reviewed-by: Ezekiel Kigbo <3397881-ekigbo@users.noreply.gitlab.com>
Reviewed-by: Anna Vovchenko <avovchenko@gitlab.com>
Reviewed-by: Diana Zubova <dzubova@gitlab.com>
Co-authored-by: Ezekiel Kigbo <ekigbo@gitlab.com>