Merge branch 'feature/helm-unittests' into 'master'

[docs] add helm unittest example

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/121776



Merged-by: Jose Ivan Vargas <jvargas@gitlab.com>
Approved-by: Hossein Pursultani <hpursultani@gitlab.com>
Approved-by: Jose Ivan Vargas <jvargas@gitlab.com>
Reviewed-by: Jose Ivan Vargas <jvargas@gitlab.com>
Reviewed-by: Marcel Amirault <mamirault@gitlab.com>
Co-authored-by: ZhekaZuev <zhekazuev@gmail.com>
Co-authored-by: Marcel Amirault <mamirault@gitlab.com>