Added Locust to README

There is an existing repo for Locust, a Python-based performance testing tool, on GitHub. I added in a link to this repository to the README to make it more accessible.

readme.md

@@ -764,6 +764,7 @@
 - [Playwright](https://github.com/mxschmitt/awesome-playwright#readme) - Node.js library to automate Chromium, Firefox and WebKit with a single API.
 - [Quality Assurance Roadmap](https://github.com/fityanos/awesome-quality-assurance-roadmap#readme) - How to start & build a career in software testing.
 - [Gatling](https://github.com/aliesbelik/awesome-gatling#readme) - Open-source load and performance testing framework based on Scala, Akka, and Netty.
+- [Locust](https://github.com/aliesbelik/awesome-locust#readme) - Open-soruce and Python-based performance testing tool
 
 ## Miscellaneous