Add image and commit badges to README

README.md

 [![Build Status](https://travis-ci.org/aquasecurity/kube-bench.svg?branch=master)](https://travis-ci.org/aquasecurity/kube-bench)
 [![License](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://opensource.org/licenses/Apache-2.0)
+[![Docker image](https://images.microbadger.com/badges/image/aquasec/kube-bench.svg)](https://microbadger.com/images/aquasec/kube-bench "Get your own image badge on microbadger.com")
+[![Source commit](https://images.microbadger.com/badges/commit/aquasec/kube-bench.svg)](https://microbadger.com/images/aquasec/kube-bench)
 
 # kube-bench