Add repo size

Author: trekhleb

README.md

@@ -9,6 +9,7 @@
 
 [![CI](https://github.com/trekhleb/javascript-algorithms/workflows/CI/badge.svg)](https://github.com/trekhleb/javascript-algorithms/actions?query=workflow%3ACI+branch%3Amaster)
 [![codecov](https://codecov.io/gh/trekhleb/javascript-algorithms/branch/master/graph/badge.svg)](https://codecov.io/gh/trekhleb/javascript-algorithms)
+![repo size](https://img.shields.io/github/repo-size/trekhleb/javascript-algorithms.svg)
 
 This repository contains JavaScript based examples of many
 popular algorithms and data structures.