docs(related): add note about helm-plugin GitHub tag

docs/related.md

@@ -35,6 +35,9 @@ or [pull request](https://github.com/kubernetes/helm/pulls).
 - [helm-nuke](https://github.com/adamreese/helm-nuke) - Plugin to destroy all releases
 - [App Registry](https://github.com/app-registry/helm-plugin) - Plugin to manage charts via the [App Registry specification](https://github.com/app-registry/spec)
 
+We also encourage GitHub authors to use the [helm-plugin](https://github.com/search?q=topic%3Ahelm-plugin&type=Repositories)
+tag on their plugin repositories.
+
 ## Additional Tools
 
 Tools layered on top of Helm or Tiller.