When building a branch like `releases/12.7`, the CI Workflow incorrectly checks out the `master` branch of `nuttx-apps`, instead of `releases/12.7`. This PR fixes a typo in `apps_ref`, to check out the correct branch.
When building a branch like `releases/12.7`, the CI Workflow incorrectly checks out the `master` branch of `nuttx-apps`, instead of `releases/12.7`. This PR fixes a typo in `apps_ref`, to check out the correct branch.