Update README.md (#1750)

Add current release version badge.

README.md

@@ -2,6 +2,7 @@
 [![Build Status](https://travis-ci.org/kubernetes/dashboard.svg?branch=master)](https://travis-ci.org/kubernetes/dashboard)
 [![Coverage Status](https://codecov.io/github/kubernetes/dashboard/coverage.svg?branch=master)](https://codecov.io/github/kubernetes/dashboard?branch=master)
 [![Go Report Card](https://goreportcard.com/badge/github.com/kubernetes/dashboard)](https://goreportcard.com/report/github.com/kubernetes/dashboard)
+[![GitHub release](https://img.shields.io/github/release/kubernetes/dashboard.svg)]()
 
 Kubernetes Dashboard is a general purpose, web-based UI for Kubernetes clusters. It allows users to
 manage applications running in the cluster and troubleshoot them, as well as manage the cluster