Mark the chart as unmaintained

README.md

@@ -2,6 +2,14 @@
 
 [![CircleCI](https://circleci.com/gh/cetic/helm-nifi.svg?style=svg)](https://circleci.com/gh/cetic/helm-nifi/tree/master) [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0) ![version](https://img.shields.io/github/tag/cetic/helm-nifi.svg?label=release) ![test](https://github.com/cetic/helm-nifi/actions/workflows/test.yml/badge.svg)
 
+## <span style="color:red">Maintainers Wanted</span>
+
+<span style="color:red">
+
+This project is not maintained anymore.
+
+If you are interested in maintaining a fork of this project, please chime in in the [dedicated issue](https://github.com/cetic/helm-nifi/issues/330).
+</span>
 
 ## Introduction