Downstream triggers does pass all variables

It seems that our downstream triggers feature does pass all variables from the job.

variables:
  MY_GLOBAL_VARIABLES: my_value

gitlab-ce:
  triggers: gitlab-org/gitlab-ce
  variables:
    GITLAB_TOKEN: my-token

We should rather pass only GITLAB_TOKEN, not MY_GLOBAL_VARIABLES.

Secondly, we should allow expanding local variables:

gitlab-ce:
  triggers: gitlab-org/gitlab-ce
  variables:
    GITLAB_TOKEN: $MY_SECRET_GITLAB_TOKEN

Futher details

Blocked without having to reference the upstream project in my downstream project- since using a dotenv file is not scalable, since I have to reference that in the downstream project.