Merge branch 'update-terraform-config' into 'master'

Resolve "Path to Base.*.gitlab-ci.yml should be relative to the root directory"

Closes #132

See merge request https://gitlab.com/gitlab-org/terraform-images/-/merge_requests/259



Merged-by: Timo Furrer <tfurrer@gitlab.com>
Approved-by: Timo Furrer <tfurrer@gitlab.com>
Co-authored-by: Yohei Kawase <ykawase@gitlab.com>