Add variables support to ci trigger

Problem to solve

We use variables a lot and would like to be able to specify variables when triggering ci jobs. glab ci run has --variables, but this is not supported in glab ci trigger

Proposal

Add variables support to glab ci trigger mirroring glab ci run. This would add the following flags

• --variables
• --variables-env
• --variables-file
• --variables-from

Further details

Example:

glab ci trigger --variables 'DEBUG:true' 123456

The curl equivalent is:

curl --request POST \
  --header "PRIVATE-TOKEN: <your_access_token>" \
  --header "Content-Type: application/json" \
  --data @variables.json \
  --url "https://gitlab.example.com/api/v4/projects/1/jobs/1/play"

Links / references

• https://docs.gitlab.com/api/jobs/#run-a-job
• https://gitlab.com/gitlab-org/cli/-/blob/main/docs/source/ci/run.md