Add event loop resource (#3921)

add a video for event loop, it's js conf in asia 2018

src/data/roadmaps/javascript/content/112-javascript-asynchronous-javascript/100-event-loop.md

@@ -7,3 +7,4 @@ Visit the following resources to learn more:
 - [The Node.Js Event Loop](https://nodejs.org/en/docs/guides/event-loop-timers-and-nexttick/#what-is-the-event-loop)
 - [JavaScript Visualized: Event Loop](https://dev.to/lydiahallie/javascript-visualized-event-loop-3dif)
 - [What the heck is the event loop anyway?](https://www.youtube.com/watch?v=8aGhZQkoFbQ)
+- [In the loop: JS conf 2018](https://www.youtube.com/watch?v=cCOL7MC4Pl0)