Mention that ANSIBLE_VAULT_PASSWORD CI variable should be declared as Type File
Following a hint from @jardellos, please consider explicitly mentioning in https://gitlab.com/Orange-OpenSource/lfn/ci_cd/chained-ci-doc/-/blob/master/howto/add_project.md#ansible_vault_password-declaration that the type of the ANSIBLE_VAULT_PASSWORD CI/CD variable is File
and not Variable
.