Fix Forgejo Workflow stuck on "Waiting"

When using Forgejo with reusable jobs, it happened to me that a job is stuck on "Waiting" without being picked up by a runner.

The docs state:

It is recommended that jobs.<job_id>.runs-on is omitted when using uses, as this will allow Forgejo to perform workflow expansion. Workflow expansion results in the target workflow’s jobs appearing in the UI as separate jobs. This provides an easier to understand experience for accessing the logs of each job, and permits the jobs to run on separate runners with their own runs-on fields.

Well, this doesn't work at all. Just add the runs-on field to the workflow reference. I have reported this bug.

Before

jobs:
  build-image:
    uses: ./.forgejo/workflows/jobs/build-image.yml
    with:
      ref_name: ${{ github.ref_name }}
      sha: ${{ github.sha }}
      registry_username: ${{ github.actor }}
    secrets: inherit

After

jobs:
  build-image:
    runs-on: docker # <-- Add this line
    uses: ./.forgejo/workflows/jobs/build-image.yml
    with:
      ref_name: ${{ github.ref_name }}
      sha: ${{ github.sha }}
      registry_username: ${{ github.actor }}
    secrets: inherit