Warn that renaming branches breaks actions

Author: jsoref

content/github/administering-a-repository/renaming-a-branch.md

@@ -15,6 +15,8 @@ You can rename a branch in a repository on {% data variables.product.product_loc
 
 When you rename a branch on {% data variables.product.product_location %}, any URLs that contain the old branch name are automatically redirected to the equivalent URL for the renamed branch. Branch protection policies are also updated, as well as the base branch for open pull requests (including those for forks) and draft releases. After the rename is complete, {% data variables.product.prodname_dotcom %} provides instructions on the repository's home page directing contributors to update their local Git environments.
 
+GitHub workflows do not follow renames, so if your repository publishes an action, anyone using that action with `@{old-branch-name}` will break. You should consider adding a new branch with the original content plus an additional commit reporting that the banch name is deprecated and suggesting that users migrate to the new branch name.
+
 Although file URLs are automatically redirected, raw file URLs are not redirected. Also, {% data variables.product.prodname_dotcom %} does not perform any redirects if users perform a `git pull` for the previous branch name.
 
 ### Renaming a branch