Add feature to release notes
### Version 3.6.0 (TBA)
* Use smaller base images for convention plugins - [Pull Request 636](https://github.com/bmuschko/gradle-docker-plugin/pull/636)
* Fully deprecate MAINTAINER instruction and replace with LABEL - [Pull Request 635](https://github.com/bmuschko/gradle-docker-plugin/pull/635)
+* Make Dockerfile task cacheable via Gradle build cache - [Pull Request 641](https://github.com/bmuschko/gradle-docker-plugin/pull/641)
### Version 3.5.0 (July 24, 2018)
* Support for dockerizing Spring Boot applications - [Pull Request 619](https://github.com/bmuschko/gradle-docker-plugin/pull/619)
