docs: add lerna badge (codesandbox#2441)

Closes: codesandbox#2424

Author: armujahid

README.md

@@ -1,4 +1,4 @@
-# [CodeSandbox](https://codesandbox.io) [![Join the community on Spectrum](https://withspectrum.github.io/badge/badge.svg)](https://spectrum.chat/codesandbox) [![All Contributors](https://img.shields.io/badge/all_contributors-142-orange.svg?style=flat-square)](#contributors) [![CircleCI](https://circleci.com/gh/codesandbox/codesandbox-client.svg?style=svg)](https://circleci.com/gh/codesandbox/codesandbox-client) [![BrowserStack Status](https://www.browserstack.com/automate/badge.svg?badge_key=cVJuczlJWUtqWXhIbFN1ZjVQekF4NzNsd3phNEZRaGlWU0pHYVVkdGRFWT0tLXFtTVhaOWRySmN0ZG5QVDNDQ0g5Z0E9PQ==--79fe3eae4f149a400d396c9b12d3988f685785cf)](https://www.browserstack.com/automate/public-build/cVJuczlJWUtqWXhIbFN1ZjVQekF4NzNsd3phNEZRaGlWU0pHYVVkdGRFWT0tLXFtTVhaOWRySmN0ZG5QVDNDQ0g5Z0E9PQ==--79fe3eae4f149a400d396c9b12d3988f685785cf) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) [![first-timers-only Friendly](https://img.shields.io/badge/first--timers--only-friendly-blue.svg)](http://www.firsttimersonly.com/)
+# [CodeSandbox](https://codesandbox.io) [![Join the community on Spectrum](https://withspectrum.github.io/badge/badge.svg)](https://spectrum.chat/codesandbox) [![All Contributors](https://img.shields.io/badge/all_contributors-142-orange.svg?style=flat-square)](#contributors) [![CircleCI](https://circleci.com/gh/codesandbox/codesandbox-client.svg?style=svg)](https://circleci.com/gh/codesandbox/codesandbox-client) [![BrowserStack Status](https://www.browserstack.com/automate/badge.svg?badge_key=cVJuczlJWUtqWXhIbFN1ZjVQekF4NzNsd3phNEZRaGlWU0pHYVVkdGRFWT0tLXFtTVhaOWRySmN0ZG5QVDNDQ0g5Z0E9PQ==--79fe3eae4f149a400d396c9b12d3988f685785cf)](https://www.browserstack.com/automate/public-build/cVJuczlJWUtqWXhIbFN1ZjVQekF4NzNsd3phNEZRaGlWU0pHYVVkdGRFWT0tLXFtTVhaOWRySmN0ZG5QVDNDQ0g5Z0E9PQ==--79fe3eae4f149a400d396c9b12d3988f685785cf) [![PRs Welcome](https://img.shields.io/badge/PRs-welcome-brightgreen.svg?style=flat-square)](http://makeapullrequest.com) [![first-timers-only Friendly](https://img.shields.io/badge/first--timers--only-friendly-blue.svg)](http://www.firsttimersonly.com/) [![lerna](https://img.shields.io/badge/maintained%20with-lerna-cc00ff.svg)](https://lerna.js.org/)
 
 [![Backers on Open Collective](https://opencollective.com/codesandbox/backers/badge.svg)](#backers)
 [![Sponsors on Open Collective](https://opencollective.com/codesandbox/sponsors/badge.svg)](#sponsors)