Merge branch 'docs-dag-feature-flag' into 'master'

Add version note for DAG feature flag

See merge request gitlab-org/gitlab!29394

doc/ci/directed_acyclic_graph/index.md

@@ -4,7 +4,8 @@ type: reference
 
 # Directed Acyclic Graph
 
-> [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/issues/47063) in GitLab 12.2.
+> - [Introduced](https://gitlab.com/gitlab-org/gitlab-foss/issues/47063) in GitLab 12.2.
+> - [Feature flag removed](https://gitlab.com/gitlab-org/gitlab/-/issues/206902) in GitLab 12.10.
 
 A [directed acyclic graph](https://www.techopedia.com/definition/5739/directed-acyclic-graph-dag) can be
 used in the context of a CI/CD pipeline to build relationships between jobs such that