docs(readme): add `lighthouse-matchers` to related projects (#16239)

readme.md

@@ -401,6 +401,7 @@ Other awesome open source projects that use Lighthouse.
 * **[lighthouse-gh-reporter](https://github.com/carlesnunez/lighthouse-gh-reporter)** - Run Lighthouse in CI and report back in a comment on your pull requests
 * **[lighthouse-jest-example](https://github.com/justinribeiro/lighthouse-jest-example)** - Gather performance metrics via Lighthouse and assert results with Jest; uses Puppeteer to start Chrome with network emulation settings defined by WebPageTest.
 * **[lighthouse-lambda](https://github.com/Otterseer/lighthouse-lambda)** - Run Lighthouse on AWS Lambda with prebuilt stable desktop Headless Chrome.
+* **[lighthouse-matchers](https://github.com/ackama/lighthouse-matchers)** - Provides RSpec matchers for executing and evaluating Google Chrome Lighthouse audit scores.
 * **[lighthouse-mocha-example](https://github.com/rishichawda/lighthouse-mocha-example)** - Run Lighthouse performance tests with Mocha and chrome-launcher.
 * **[lighthouse-monitor](https://github.com/verivox/lighthouse-monitor)** - Run Lighthouse against all your URLs. Send metrics to any backend you want, save all reports with automatic data retention, and compare any two results in a web UI.
 * **[lighthouse-persist](https://github.com/foo-software/lighthouse-persist)** - Run Lighthouse and upload HTML reports to an AWS S3 bucket.