feat: the new `forgejo-runner validate` command can be used to verify if an action or a workflow is conformant with the expected schema. `forgejo-runner validate --repository https://example.com/my/repository` will validate all the workflows and actions a Git repository contains. Alternatively  `forgejo-runner validate --path myaction/action.yml --action` or `forgejo-runner validate --path .forgejo/workflows/test.yml --workflow` can be used to validate a single file. It is recommended to use these commands to verify existing actions and workflows pass before upgrading to [Forgejo runner v8.0.0](https://code.forgejo.org/forgejo/runner/src/branch/main/RELEASE-NOTES.md#8-0-0) or above to not disrupt existing workflows.
