Add data structure content (#2079)

* Added one of the best and new resource to the java datastructures list

* Update content/roadmaps/110-java/content/100-java-fundamentals/104-datastructures.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/110-java/content/100-java-fundamentals/104-datastructures.md

@@ -6,3 +6,4 @@ As the name indicates itself, a **Data Structure** is a way of organizing the da
 <BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.geeksforgeeks.org/data-structures'>What are Data Structures?</BadgeLink>
 <BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.javatpoint.com/data-structure-tutorial'> Data Structures and Algorithms</BadgeLink>
 <BadgeLink badgeText='Watch' href='https://www.coursera.org/learn/data-structures'>Data Structures and Algorithms</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.pepcoding.com/resources/'>Practice Data Structures</BadgeLink>