chore: adding keploy to the list of shadow testing tools

docs/automated-testing/shadow-testing/README.md

@@ -32,6 +32,7 @@ There are some tools to implement shadow testing. The main purpose of these tool
 - [Envoy](https://www.envoyproxy.io)
 - [McRouter](https://github.com/facebook/mcrouter)
 - [Scientist](https://github.com/github/scientist)
+- [Keploy](https://github.com/keploy/keploy)
 
 One of the most popular tools is [Diffy](https://github.com/opendiffy/diffy). It was created and used at Twitter. Now the original author and a former Twitter employee maintains their own version of this project, called [Opendiffy](https://github.com/opendiffy/diffy). Twitter announced this tool on their engineering blog as "[Testing services without writing tests](https://blog.twitter.com/engineering/en_us/a/2015/diffy-testing-services-without-writing-tests.html)".