Make yamllint happy

roles/custom/matrix_playbook_migration/tasks/validate_config.yml

@@ -172,4 +172,3 @@
           Please change your configuration (vars.yml) to rename all variables (`matrix_aux_` -> `aux_`).
           We found usage of the following variables: {{ matrix_playbook_migration_aux_migration_vars.keys() | join(', ') }}
       when: "matrix_playbook_migration_aux_migration_vars | length > 0"
-