Fixed workflow:rules release version in docs

doc/ci/yaml/README.md

@@ -1024,16 +1024,16 @@ Additional job configuration may be added to rules in the future. If something
 useful isn't available, please
 [open an issue](https://gitlab.com/gitlab-org/gitlab/issues).
 
-#### `workflow:rules`
+### `workflow:rules`
 
-> Introduced in Gitlab 12.6
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/issues/29654) in GitLab 12.5
 
 The top-level `workflow:` key applies to the entirety of a pipeline, and will
 determine whether or not a pipeline is created. It currently accepts a single
 `rules:` key that operates similarly to [`rules:` defined within jobs](#rules),
 enabling dynamic configuration of the pipeline.
 
-The only configuration options currently available for `workflow:rules` are:​
+The configuration options currently available for `workflow:rules` are:​
 
 - [`if`](#rulesif): Define a rule.
 - [`when`](#when): May be set to `always` or `never` only. If not provided, the default value is `always`​.