chore: add resource under angular:typescript-basics:type-guard

src/data/roadmaps/angular/content/100-typescript-basics/106-type-guard.md

@@ -9,3 +9,4 @@ Type guards are typically used for narrowing a type and are pretty similar to fe
 Visit the following resources to learn more:
 
 - [Types Guards - Blog](https://blog.logrocket.com/how-to-use-type-guards-typescript/)
+- [TypeScript Type Guards Explained](https://www.youtube.com/watch?v=feeeitmtdwg)