plan.cache: no matching files, unable to attach terraform report to the MR

Question

I have following plan stage in my gitlab CI, which I took from here but unlike gitlab-terraform, terraform v1.1.0 doesnt have any option of plan-json, so I am trying to reproduce the same with the following. Aim is attached the plan changes as report in gitlab merge requests.

plan:
  stage: plan
  script:
    - terraform plan -out=plan.json 
    - terraform show -json plan.json
  artifacts:
    name: plan
    paths:
      - ${TF_ROOT}/plan.cache
    reports:
      terraform: ${TF_ROOT}/plan.json

However, in MR all I see is 1 Terraform report failed to generate and in the complete job log I see following:

plan.cache: no matching files 
12ERROR: No files to upload 

Question is what is the difference between artifacts:path and the path given under artifacts:reports:terraform. and,

Where can I find/generate plan.cache?

$ terraform -v
Terraform v1.1.0