Note on default value for artifacts

doc/ci/yaml/README.md

@@ -1944,7 +1944,7 @@ Feature::enable(:ci_dag_limit_needs)
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/14311) in GitLab v12.6.
 
-When using `needs`, artifact downloads are controlled with `artifacts: true` or `artifacts: false`.
+When using `needs`, artifact downloads are controlled with `artifacts: true` (default) or `artifacts: false`.
 The `dependencies` keyword should not be used with `needs`, as this is deprecated since GitLab 12.6.
 
 In the example below, the `rspec` job will download the `build_job` artifacts, while the