docs: add unit testing badge

Author: developher-net

README.md

@@ -1,6 +1,7 @@
 # aem-packager-example
 
 [![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)
+[![Run Tests](https://github.com/amclin/aem-packager-example/actions/workflows/run-tests.yml/badge.svg)](https://github.com/amclin/aem-packager-example/actions/workflows/run-tests.yml)
 
 This is a simple example NodeJS project using [aem-packager](https://www.npmjs.com/package/aem-packager) and [aem-clientlib-generator](https://www.npmjs.com/package/aem-clientlib-generator) to build deployable content packages that can be installed into Adobe Experience Manager via the AEM Package Manager.