Support workflow_ref in the github context

[buzden]

According to the documentation, github context contains workflow_ref property.

Attempt to use it in the workflow yaml, say

concurrency:
  group: ${{ github.workflow_ref }}
  cancel-in-progress: true

leads to

2023-01-17 11:06:17 [ERROR]   Found errors in [actionlint] linter!
2023-01-17 11:06:17 [ERROR]   Error code: 1. Command output:
------
.github/workflows/ci-random-pure.yml:19:14: property "workflow_ref" is not defined in object type {action: string; action_path: string; action_ref: string; action_repository: string; action_status: string; actor: string; api_url: string; base_ref: string; env: string; event: object; event_name: string; event_path: string; graphql_url: string; head_ref: string; job: string; path: string; ref: string; ref_name: string; ref_protected: string; ref_type: string; repository: string; repository_owner: string; repositoryurl: string; retention_days: number; run_attempt: string; run_id: string; run_number: string; server_url: string; sha: string; token: string; triggering_actor: string; workflow: string; workspace: string} [expression]
   |
19 |   group: ${{ github.workflow_ref }}
   |              ^~~~~~~~~~~~~~~~~~~
------

but should be accepted instead.