docs(readme): add link to a poll in discussions

Author: gund

README.md

@@ -12,6 +12,9 @@
 [![semantic-release](https://img.shields.io/badge/%20%20%F0%9F%93%A6%F0%9F%9A%80-semantic--release-e10079.svg)](https://github.com/semantic-release/semantic-release)
 [![Greenkeeper badge](https://badges.greenkeeper.io/gund/ng-dynamic-component.svg)](https://greenkeeper.io/)
 
+> Hey! There is a [proposal for new API](https://github.com/gund/ng-dynamic-component/discussions/484)
+> so if you are using this library please give your vote/feedback.
+
 <details>
   <summary>Compatibility with Angular</summary>