Added "Learn React for free" course from Scrimba (#7920)

* Added "Learn React for free" course from Scrimba

* Fixed linting issues

courses/free-courses-en.md

@@ -724,6 +724,7 @@
 * [Frontend Armory: React Fundamentals](https://frontarm.com/courses/react-fundamentals/) - James K. Nelson
 * [Full Modern React Tutorial](https://www.youtube.com/playlist?list=PL4cUxeGkcC9gZD-Tvwfod2gaISzfRiP9d) - The Net Ninja (with practical)
 * [Full-Stack Web Development with React Specialization](https://www.coursera.org/specializations/full-stack-react) - Jogesh K. Muppala (Coursera)
+* [Learn React for Free](https://scrimba.com/learn/learnreact) - Bob Ziroll (scrimba)
 * [React](https://progate.com/languages/react) (progate) *(account required)*
 * [React basic in just 1 hour](https://www.udemy.com/course/react-basic-in-just-1-hour/) (Udemy)
 * [React Context & Hooks Tutorial](https://www.youtube.com/playlist?list=PL4cUxeGkcC9hNokByJilPg5g9m2APUePI) - The Net Ninja