Rename 'hocs' folder to 'hoc'

Author: Aljullu

src/hocs/trackWindowScroll.js renamed to src/hoc/trackWindowScroll.js

@@ -1,2 +1,2 @@
 export { default as LazyLoadImage } from './components/LazyLoadImage.jsx';
-export { default as trackWindowScroll } from './hocs/trackWindowScroll.js';
+export { default as trackWindowScroll } from './hoc/trackWindowScroll.js';